Method of operating an arc source and method for depositing electrically insulating layers

ES 2 445 397 T3

DESCRIPTION

Procedure for the operation of an arc source and procedure for separating electrical insulating layers

Technical scope

The invention relates to a method according to the preamble of claim 1 for the operation of an arc source.

State of the art

In the state of the art, different procedures are known for the operation of arc sources, also known as arc vaporizer sources or spark sources, by means of the combination of a direct current source and a power source with pulses of current.

In document EP 0 666 335 B1, for example, it is proposed that a pulsating current is superimposed on an arc vaporizer, operating with direct current, to vaporize good conductive materials. In this way, current pulses of up to 5000 A are obtained, which, with relatively low pulse frequencies in the range of 100 Hz to a maximum of 50 kHz, are generated by discharges of capacitors. This is to essentially reduce, among other things, the formation of small droplets in the vaporization of pure metal targets. Individual discharges of capacitors are used to generate the different obtainable forms of the pulsed current pulses. In this case, for example in the creation of a rectangular current impulse, a short-term increase in the discharge voltage takes place, but which cannot be kept constant, but falls again, since, due to Low plasma impedance in the spark discharge immediately increases the intensity of the spark, the consequence of which is a drop in the discharge voltage of the capacitor and thus the discharge voltage of the spark. Despite the supposed positive effect of short-term voltage peaks, it is not possible to maintain a higher spark discharge voltage for a long time.

Against this, procedures are known through documents WO 2008/043606, respectively US 2008/090099, which, in addition to the procedure disclosed in document EP 0 666 335 B1 already mentioned, describe pulsed spark currents for the vaporization of metals in a reactive gas atmosphere, which are used to manufacture insulating layers, especially oxidic ones. In these processes, both the advantageous effect of the pulsation on the reduction of spatter is described, as well as the operation of the spark target in the atmosphere of reactive gas, especially in oxygen. Furthermore, in these applications the importance of the slope of the voltage pulse superimposed on the spark discharge voltage is discussed for the first time. The present application is based on this invention.

Exhibition of the invention

The invention is based on the problem of creating a process in which the drawbacks of the state of the art mentioned above are avoided and the advantages of a high ionization of a spark discharge can be combined with the advantage of a higher discharge voltage. without subjecting the spark cathode, especially the surface of the spark cathode, to excessive thermal load. This problem is solved with the features of claim 1.

In this case an electric spark discharge is ignited, respectively operated on the surface of a target, and the spark discharge is carried out at the same time with a direct current and a relatively low direct voltage from a power source. At the same time, a pulsating current generated with a periodically applied voltage signal is injected, and the shape of the voltage signal can be chosen essentially freely.

In principle there are different possibilities to pulse the spark current and thereby increase and form the spark discharge voltage.

The use of a pulsed power supply, which supplies the current for the discharge of the spark, would be the simplest from the point of view of its premises. However, it was found that with the usual generators of the state of the art for switching on / pulsing of large currents these premises do not lead or at least lead only insufficiently to a constant increase in the spark discharge voltage, at least for the duration of the applied signal. Voltage increases are not fast enough and steeper edges cannot be obtained with higher frequencies, since it is difficult or impossible to obtain these with high spark intensities of the order of 100 A or more. The result of the application of a pulsed signal of this kind is only a short duration voltage peak with a small amplitude, which is compensated by an increase in intensity adapted to the applied power and with the plasma impedance reduced the rapid increase of the offer carriers of loads. Also the combination of two separate power supplies of which one operates in a pulsed manner, does not lead to essential improvements.

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According to the present invention, an arc source is operated with a method according to claim 1. In this case, the spark current can be operated by means of the parallel connection of a pulsed voltage source, which can supply powers. high in impulse to ensure the desired shape of the voltage signal. As will be described below, this can be done for example with a sufficiently rapid succession in time of several capacitor discharges or with the use of a specially designed power supply.

The advantages obtained with the invention reside, inter alia, in the fact that with one control, respectively the possibility of improved adjustment of the intensity / voltage range of the spark discharge for target materials and for different process conditions can be adjusted working ranges with which it is possible to separate layers with a known high coating rate in spark vaporization, which have a clearly improved quality in relation to the formation of spatters on the surface of the object to be coated.

This is not only valid for the separation of metal layers, but especially also for the synthesis of layers in reactive processes and at the same time with high separation rates. Thus, for example, the vapor of the target ionized to an even greater part than in conventional spark-discharge processes can react to form a corresponding layer-forming compound with the reactive gas also ionized, respectively also dissociated at least in part in the plasma, respectively on the surface of the part to be coated. In addition to the large number of compounds of hard materials, such as nitrides, carbides, carbonitrides, borides, silicon compounds and other compounds of one or more transition metals of group IV, V and VI of the periodic system of elements ( according to the IUPAC-Standard 2005) as well as aluminum, the possibility of also obtaining oxidic layers or other insulating layers with this procedure should be emphasized here. This pulsed process is especially advantageous in carbon spark vaporization. In this material it is difficult to deflect the cathodic spark with a pure direct current power supply. The superposition of voltage pulses appears to influence the electron emission properties in such a way that "seizure" of the spark stem is prevented and hard hydrogen-free carbon layers such as ta-C can be separated. The term "seizure" is understood here to mean that the foot of the spark remains for a long time in a very small area of ​​the target surface, which, especially in carbon targets, often leads to a deterioration of the surface, the greatest formation spatter as well as a reduction in the coating rate.

For the production of mixed crystals with a corundum structure, arcing processes with, respectively, a specially designed small perpendicular magnetic field and superimposed pulse arcing processes as well as general processes, such as arcing or spraying processes, are suitable. cathodic, in which sources of material, such as arc sources, respectively sputtering sources, high current pulses are applied, respectively superimposed on basic DC operation. In this way, the operation in the contaminated state, respectively the formation of an alloy on the target, is possible, provided that certain marginal conditions set out below in detail are respected.

In pulse source processes for the production of particularly thermally robust multi-oxide mixed crystal layers in the corundum-type crystal lattice, at least one arc source is supplied simultaneously with direct current and also with pulsating current, respectively alternates. In this case, a layer is deposited on the part with a first electrode constructed as an alloy target of an arc or sputtering source as well as with a second electrode, the source being supplied at the same time with a continuous current, respectively a voltage continuous and also a pulsating or alternating intensity, respectively a pulsating or alternating voltage. The alloying white here essentially corresponds to the composition of the mixed glass layer. The preferred pulse frequency is in this case in the range from 1 kHz to 200 kHz, the pulse current supply being able to operate also with a different pulse width ratio, respectively with pulse pauses.

The second electrode can in this case be arranged separately from the arc source or as an anode from the arc source, the first and second electrodes connected with a single pulsating current source being able to function. If the second electrode does not function as the anode of the arc source, the arc source can be connected respectively through the pulsating current source with one of the following material sources:

- a second arc vaporizer source also connected to a direct current power source;

the cathode of a sputtering source, especially a magnetron source, also connected to a power source, especially a direct current power source;

- a vaporizing crucible, which functions at the same time as the anode of a low-voltage arc vaporizer.

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The supply with direct current takes place in this case with a basic intensity such that the plasma discharge remains essentially uninterrupted at least in the arc vaporizer sources, but preferably in all sources. In this case, the direct current supply and the pulsed current supply are decoupled with an electrical decoupling filter, preferably containing at least one blocking diode. Coating can take place in this case at temperatures below 650 ° C, preferably below 550 ° C.

As an alternative to the spark vaporization, the formation of the layer can also essentially take place exclusively with the decomposition of gaseous precursors, provided that the optical connection between the workpiece and the spark source is interrupted, for example by diaphragms or other measures. constructive. By way of example, various DLC or diamond layers are mentioned here, such as those described inter alia in VDI 2840, Table 1, silicon nitride, boron nitride and analogous systems. Many of these layers can also be separated with combined processes in which a part of the layer-forming material comes from the gas phase and another part from the plasma of a sputtering or spark cathode.

With a method of this kind, it is also possible to control, by adjusting the height and the slope of the flanks of the periodically applied voltage signal, respectively of the needle pulses, which form the voltage signal, the emission electron discharge spark . This is all the more intense, the higher the voltage signal, respectively the needle pulse, the steeper the corresponding flank of the voltage increase is selected.

If an electric spark discharge is operated with a direct current and with a pulsating current generated with a voltage signal applied periodically, it is advantageous that the frequency of the voltage signal is set between 1 Hz and 200 kHz, preferably between 10 Hz and 50 kHz. The shape of the voltage signal can in this case be, for example, a saw tooth, a polygon or a trapezoid, a rectangular shape being preferred for many applications, owing to the particularly rapid increase in voltage to the full amplitude and to the permanence at this voltage level PV for the entire duration Tp of the pulse.

The voltage signal, respectively the voltage generator can also operate with gapped pulses, that is to say with a pulse length of less than half the duration of the operating frequency period.

Due to the high degree of ionization of the plasma generated with the spark discharge and the number of existing charge carriers in a sufficient quantity, it also increases immediately to intensity or only with a delay in the range of a few microseconds. Given, however, that the transport of charges, on the one hand, in plasma takes place both by means of electrons, and also by means of ions and that the latter have a certain inertia and, on the other, other resistances As for example the impedances of the cables in the spark circuit play a role, it is not possible for the intensity to immediately follow the pulsed voltage signal to the same extent. This effect can be exploited in the present method by applying voltage signals with a very large amplitude, which without limiting in time the length of the pulses, respectively of the needle signals as will be described below, would give rise to an overload. from the voltage generator, to the formation of harmful electrical discharges, to the deterioration of the target surface, to a process interruption or other unwanted phenomena. As an alternative or additional safety measure, it can also be generated to limit the increase in the damaging intensity due to the pulse frequency, respectively the frequency of the needle pulses by switching off the voltage signal, when exceeded. a detected intensity threshold. In both cases, pulse pauses can be provided by the technician as required, which can be determined for example by setting the corresponding time constants of the voltage pulse, pulse pauses adapted for example by means of the above-mentioned gap operation. above, to optimize the signal curve for processes with, for example, different material from the target or with a different process composition.

The shape of the signal is advantageously obtained in this case from that resulting from a succession of needle pulses, which are generated for example with the time-controlled sequence of the discharge of individual capacitors. The slope of the flanks of the needle pulses should in this case be at least 0.5 V / ps, but preferably at least 2 V / ps and thus also determines the slope of the voltage signal formed by the resulting. The sequence, respectively the duration of the needle pulses can be set between 0.1 kHz and 1 MHz, respectively 10 ms and 1 ps, but preferably between 1 kHz and 500 kHz, respectively 1 ms and 2 ps. As already mentioned, it is especially advantageous if the needle pulses are chosen in such a way that the resultant has a quasi-stationary voltage curve during the pulse duration Tp, that is, it has approximately a rectangular shape, in order to be able to maintain The desired emission processes at the cathode are stable for the duration of the pulse.

The absolute magnitude of the amplitude of the needle pulses, respectively of the voltage signal should in the present case exceed the applied direct current by at least 10%, but preferably by at least 30% to obtain the desired effects of increased ionization, etc.

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The advantage of such a sequence of capacitor discharges resides in the fact that very high powers of the pulses, for example a few hundred kW per pulse, can be realized. In comparison to this, spark targets operate in the system with direct current with typically 5 to 10 kW. A high-frequency superposition with these high-power pulses with a single capacitor discharge would, however, lead to an overload of the source and / or other parts of the arrangement and would not guarantee the desired voltage stability for the duration of the operation. impulse. These high-energy capacitor discharges are therefore suitable for frequency ranges up to about 10, but at most 50 kHz. The discharge of capacitors with a smaller capacity and their juxtaposition in time can also take place at higher frequencies, as the technician well knows.

These voltage signals, respectively the corresponding sequence of needle pulses, can also alternatively be supplied with one or more freely adjustable power supplies from the point of view of the signal length, the signal frequency, the amplitude of the signal. the signal, the pulse pauses and / or the shape of the signal, provided that these are designed to generate pulsed voltage signals with a large slope of the flanks. A voltage power supply of this kind is described in detail, for example, in document WO 06099759. The corresponding application, in particular the description of the use of such a voltage power supply, called there vacuum plasma generator , from page 14, paragraph 2 to page 17 below, hereby declared an integral part of the present patent application. With a generator of this class it is also possible to realize edge slopes from 0.1 V / ns to 1.0 V / ns.

The use of voltage power supplies of this class is especially recommended when high pulse frequencies must be used, for example between 10 and 200 kHz. In this case, it must be borne in mind that the use of a pulsed voltage source, respectively a voltage power source, is always a compromise between the achievable pulse energy and the possible frequency.

To further increase the thermal excitation on the target surface, some tests were also carried out with cooled targets, respectively heated, vaporizing material from the almost incandescent target surface under oxygen. The layers thus obtained also show a corundum-type weft. In these processes, it is possible to observe at the same time, through the increase in the discharge voltage, an increase in the impedance of the plasma, which can be attributed to the higher emission of electrons from incandescent surfaces in combination with a higher vapor pressure of the target material and which is further strengthened by the pulsation of the source current.

Another possibility for obtaining oxide layers according to the invention is the operation of a high-power discharge with at least one source. This can be generated, for example, by using pulsed current power supplies, respectively pulsed voltage power supplies with a slope of the pulse flanks, which is at least in the range of 0.02 V / ns to 2.0 V / ns, preferably in the range 0.1 V / ns to 1.0 V / ns. In this case, currents of at least 20 A are applied, but preferably equal to or greater than 60 A with voltages between 60 and 800 V, preferably between 100 and 400 V above, respectively, in addition to the voltage and the discharge current. direct current performed at the same time. These voltage needle pulses can be generated for example with one or more cascades of capacitors, which, together with other advantages, also makes it possible to reduce the load on the basic power supply. However, the pulse generator is connected between two arc sources, which operate simultaneously with direct current. With the application of the needle pulses in the arc procedure, it is surprisingly possible to increase the voltage at the source for several ps as a function of the magnitude of the applied voltage signal, while the pulses with a lower slope of the flanks are only manifest, as expected, in an increase in the intensity of the source.

As the first tests showed, with these high intensity discharges it is also possible to obtain with sputtering sources with alloy targets multiple oxides with comparable corundum, scholaite or hexagonal structures, which is supposedly due to the higher power density in the surface of the target and the large increase in temperature associated with it, in this case also the use of cooled or heated targets, as described above. For these processes, high-power discharge has similar characteristics, both for the use of high-power arcs and for high-power sputtering, such as those that correspond to the abnormal effluvia discharge known from the Townsend diagram of intensity and tension.

Fundamentally different measures are possible to increase the impedance of the plasma, respectively of the target surface. This can be achieved, as discussed above, by superimposing needle pulses, heating the target surface, or a combination of measures. The term "superposition" here is understood to mean a superposition of the direct current discharge voltage with needle pulses, which does not exclude the overlap in time of the needle pulses, in the sense of a sequence of needle pulses, which overlap at least partly. It is obvious to the technician that, in order to achieve particularly high powers, it is also possible to discharge at the same time, for example, two or more capacitors and thus form a particularly large needle pulse.

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Brief description of the drawing

In the following, the invention will be described in detail by means of figures, which only represent different exemplary embodiments of the present invention. These show:

FIG. 1, a spark coating installation with direct current and pulsed current supply;

FIG. 2 a spark coating installation with direct current supply and pulse capacitor; FIG.

Figure 3, a diagrammatic tension strap;

Figure 4 a schematic voltage / current curve;

Figure 5, a measured voltage / current curve.

The vacuum treatment installation 1 represented in FIG. 1 contains an arrangement for the operation of an arc source combined with a generator unit 16, which contains a direct current power source 13 and a pulsed voltage source 15 connected to parallel to it, in this case a voltage supply source 15, to superimpose a pulsed voltage signal on the direct current. This connection allows stable operation of a reactive spark vaporization even for insulating layers, in which in the course of time the interior of the installation 1, the auxiliary anode 10 and the substrate supports 3, respectively, are covered with an insulating layer. the substrate. The installation is equipped with a pump station to create the vacuum, substrate supports 3 to house and electrically contact the parts not represented here, as well as a bias current supply source 4, to apply a substrate voltage to the parts. The latter can be a direct current power supply, an alternating current power supply or a bipolar power supply respectively unipolar substrate. Via at least one process gas inlet 11, inert gas, respectively reagent, can be injected to control the process pressure and the gas composition in the treatment chamber.

The components of the arc source itself are a target 5 with an ignition finger 7 as well as an anode 6, which surrounds the target 5. With a switch 14 you can choose between floating operation of the anode and the positive pole of the source. 13 power supply and operation with zero potential, respectively defined ground. Furthermore, the arc source may also comprise a target magnetic system 12, for example one or more coils and / or a permanent magnet system.

Other optional characteristics of the vacuum treatment installation 1 are an additional plasma source 9, in this case a source for generating a low voltage arc with hot cathode, with input 8 for inert gas, an auxiliary anode 10 as well as another power supply not represented here in detail for the operation of the low voltage arc between the plasma source 9 and the auxiliary anode 10 and, if necessary, coils for the magnetic concentration of low voltage electric arc plasma.

In figure 2, the pulsed voltage source is composed of at least one power supply 18 with load voltage to charge several capacitors of groups 19 of capacitors and of the corresponding switches 20, which connect the capacitors 19 in a time-controlled manner. with the power supply with load voltage for its load or with the arc source to generate a needle pulse. For the sake of simplicity, only one capacitor 19 and one switch 20 are shown in FIG. 2, representing a corresponding arrangement of capacitors and switches. The power supply 18 with load voltage generates in this case, for example, a constant voltage between 100 and 1000 V, while the operating voltage of the power supply 13 with direct current also integrated here in a generator unit 16 It is, in the range of the usual operating voltages for spark-discharge generators, between about 10 to about 100 V.

Figure 3 shows a possible voltage curve, which can be obtained with a corresponding activation of the switches 20. In this case a series of capacitor discharges are juxtaposed in such a way that the resultant 21 of the needle pulses 22 generated with the discharges of the capacitors generate the form of the pulsed voltage signal with a voltage Pv of the pulses. The idealized resultant 21, which is essentially equivalent to the actually measured voltage, is found, with needle pulses of the same magnitude, at approximately two-thirds of the height of the maximum needle voltage and can be superimposed on impedance-based ripple and in the separation of the needle pulses. The needle pulses 22 are represented here schematically as triangles and without gaps. It is obvious that the needle pulses can also have different shapes and that they can be juxtaposed with interstices. The pulsed voltage signals in this case are based on the low voltage direct current signal generated with the direct current power supply 13. With the rapid packet succession of the needle pulses 22 with the duration Tn the voltage rise PV-DV can be kept stable for a long time interval Tp, but it can at least be kept stable until a

ES 2 445 397 T3 pulse signal with medium frequency with duration Tf. The shape of the signal can be varied with the application, known to the technician, of pulses of water with different height, respectively length, respectively by adapting the discharges of the capacitors to the impedance of the spark discharge. In the case of a rectangular signal it is possible that the rising edge 23 of the resultants 21 has the same slope as the needle pulses, provided that the capacity of the individual capacitor is chosen sufficiently large. Alternatively, a large number of smaller capacitors can be connected in a synchronized manner, as is known to the technician, to obtain a corresponding voltage signal. Tf can be set in this case between 5 ps and up to 1 s, but preferably between 20 ps and 100 ms. As already mentioned, gap operation is also possible. Tn can be set between 1 ps and 100 ms, but preferably between 2 ps and 1 ms. If extremely short voltage signals are desired, the voltage signal can be formed with a single needle pulse. In this case, only the formation of a voltage peak takes place. However, the advantage of the present method of being able to freely adjust the shape of the signal can only be exploited with a minimum sequence of three, preferably five, in particular ten needle pulses. The time during which the full pulse voltage can be applied, when using a rectangular pulse, is at least three, five, respectively 10 microseconds, preferably at least six, fifteen, respectively thirty microseconds. The maximum duration can be determined in the case of a time delay with half the frequency of the voltage signal.

In a similar way, very steep and well-defined voltage signals can also be produced with a voltage source, such as that described for example in WO 06099759, which can also be formed by a packet of successive needle pulses, to obtain a corresponding increase in spark discharge voltage.

Figure 4 represents the behavior in principle of the voltage / current for the operation of these pulsed voltage sources connected in parallel. Figure 4A shows analogously to Figure 3, the details to generate the resultant 21, the voltage curve of the spark voltage resulting from the power supply source 13 with direct current (dotted line) and the source 15 , respectively 18 to 20 of the pulsed voltage (solid line). Figure 4B shows the corresponding intensity curve. The increase in the intensity of the spark current takes place practically immediately after the application of the pulsed signal with the PV height by means of the pulsed voltage source and thereby increases the discharge current, which flows through the plasma of spark discharge. It should be noted that in Figures 4 and 5 the sum curve of the discharge current is not represented, but separately the curves of the currents generated by the pulsed voltage source (solid line), respectively by the DC power supply 13 (dotted line). While the voltage of the spark reaches the nominal value very quickly, which can be kept practically stationary over the length of the pulse, the intensity of the spark increases quasi linearly throughout the duration of the pulse with a manifestly smaller slope determined by the impedances of cables and by other resistors in the spark circuit. The intensity of the spark does not reach saturation in this case, as could also be expected according to the Townsend diagram. Only the disconnection of the voltage impulse and the spark discharge voltage drop causes the spark intensity to decrease again. Therefore, in principle it is possible to obtain with pulsed voltage sources, which are connected in parallel with the power supply with direct current of the spark, almost stationary increases of the spark discharge voltage. The slope and the value of the voltage rise in pulsed operation here depend on various parameters, such as the impedances of the cables, the impedance of the discharge, the material of the target, etc. The slope of the impulse and the amplitude of the voltage rise also influence each other. The steeper the voltage pulse can be configured, the greater is the possible increase in voltage due to the relative inertia of current growth. However, through figure 4 it is also understood that the length of the impulse cannot be unlimitedly large, since the voltage overshoot gives rise to the drag of the spark intensity, which also leads, usually when reaching a threshold value, also called short-circuit current, to the automatic disconnection of the supply with direct current. This automatic switch-off point can also be used, together with the limitation by means of the length Tp of the voltage signal and the length Tn, respectively the sequence and arrangement of the needle pulses, to control the increase in intensity and of the vaporization process on the spark cathode linked to it.

Figure 5 shows the current-voltage curve, recorded during a pulsed coating process indicated below, with an Upuls voltage signal periodically applied by a pulsed voltage power supply 15 and with a corresponding pulsed Ipuls current, which it is superimposed on the direct current Idc from the direct current power supply 13. Also in this case it can be seen that the intensity Ipuls of the impulse increases, even after reaching the PV voltage of the impulse, until the impulse is switched off. The voltage surge in relation to direct current operation is in this case approximately -20 V.

The intensity-tension curves represented were recorded in the separation of layers of Al2O3, respectively (Al, Cr) 2O3 in an Innova production system from Oerlikon Balzers under the following conditions.

1. Process parameters for spark vaporization to obtain aluminum oxide:

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<td>Oxygen flow</td><td>400 sccm</td>

<td>Process pressure</td><td>1x10^-2 mbar</td>

<td>DC source intensity, Al white</td><td>100 A</td>

<td>Pulse source intensity, Al target</td><td>100 A at 50 kHz, 10 ps pulse / ps pause</td>

<td>Substrate bias</td><td>-40 V pulsed with DC or AC (always 50-350 kHz)</td>

<td>Substrate temperature</td><td>approx. 500 ° VC</td>

<td>Processing time</td><td>60 to 120 min, some trials with 360 min</td>

The measured rise time of the rising edge 23 of the resulting voltage pulse was approximately 6 V / ps.

two. Process parameters for spark vaporization to obtain mixed aluminum / chromium oxide crystals with a corundum structure:

<td>Oxygen flow</td><td>1000 sccm</td>

<td>Process pressure</td><td>2.6x10^-2 mbar</td>

<td>DC source intensity, Alü, 7Cr0.3</td><td>120 A</td>

<td>Pulse source intensity, Alü, 7CrQ, 3</td><td>100 A, 30 kHz 8 ps boost / 25 ps pause</td>

The coil current of the source magnetic field, type Oerlikon Balzers MAG 6, was set at 0.5 A. Thereby an essentially perpendicular weak field of about 2 mT (20 Gs) was generated at the target surface.

<td>Substrate bias</td><td>U = -60V (bipolar, 36 ps negative, 4 ps positive)</td>

<td>Substrate temperature</td><td>approx. 550 ° C</td>

<td>Process time</td><td>60 to 120 min</td>

<td>The measured rising edge 23 growth time of approximately 2 V / ps.</td><td>the resultant of the voltage impulse was</td>

By means of a corresponding adaptation of the impulse voltage supply, for example by choosing very short cable connections to the spark sources, it was possible to obtain slopes up to 100 V / ps.

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LIST OF REFERENCE SYMBOLS

Spark Coating Installation

Vacuum pump station

Substrate support

Bias boost feeding

White

Anode

Ignition device

Ionization chamber

Filament

Auxiliary anode

Gas inlet

Magnetic Target System

DC power supply

Ground switch

Pulsed voltage supply

Generator unit

Coil

Power supply with load voltage

Condenser

Pulse switch

Resulting

Needle pulse

Rising edge