SU761603A1 - Device for electric arc evaporation in vacuum - Google Patents

Description

The invention relates to vacuum technology and technology and can be used both to obtain various coatings in a vacuum, and as a highly efficient sublimator for evaporation of getter materials in various types of sorption vacuum pumps.

A device for evaporating conductive materials in vacuum, containing a movable cathode made of evaporating material, an anode, a magnetic coil, a pulsed arc excitation system, made in the form of an insulator separating the working surface of the cathode from the anode surface, which periodically with a frequency equal to the frequency after the impulses, a conductive film of the evaporating material of the cathode and a single-phase half-wave AC current source is applied [1].

However, the known power scheme does not allow to power the device from a multi-phase AC network.

The closest to the proposed

technical entity is a device

for arc evaporation in vacuum,

containing two electrodes, one of which

made of evaporating material with

the possibility of moving, a magnetic coil, an insulator separating the working surface of the electrodes, a multi-phase power source with a transformer [2].

'A disadvantage of the known device YaV ₅ insufficient wish to set up the control range of evaporation rates.

The purpose of the invention is to increase the range of regulation of the rate of evaporation.

This goal is achieved by the fact that in a device for electric arc evaporation U in a vacuum containing two electrodes, one of which is made of evaporating material for movement, a magnetic coil, an insulator separating the working surface of the electrodes, a multiphase power source with a transformer, one of the electrodes is connected with a multi-phase power supply transformer through a group of controlled valves, and the other is connected to the zero output of the mentioned transformer.

FIG. 1 shows a schematic diagram of the power of the evaporator from a two-phase network; in fig. 2 - the same for the case of three-phase power.

761603

3

The evaporator consists of a cathode 1 made of evaporating material, an anode 2, a magnetic coil 3 creating a magnetic field in the interelectrode gap, and an insulator 4 dividing the surface 5 of the q т t 1 from the surface of the anode 2. The cathode 1 of the device can be connected either zero output of the supply transformer 6, as shown in FIG. 1, or with an anode group of controlled valves 7, as shown in FIG. 2. Accordingly, the anode 2 of the evaporator can be connected either to the cathode valve group, as shown in FIG. 1, or to the neutral terminal of the transformer 6, as shown in FIG. 2

To limit the current in the zero circuit can be included resistance 8. The same role can be played by the winding of the magnetic coil 3, which can be included in the zero circuit in series with the arc discharge gap. Regulation of the average current and, consequently, the rate of evaporation is provided by the control unit 9. The evaporating material of the cathode is ionized in a vacuum arc burning between cathode 1 and anode 2, focused into the plasma jet 10 and accelerated by means of coil 3 towards the condensation surface.

The device works as follows.

 When a signal from the control unit 9 is applied to one of the controlled valves 7, the latter opens to the cathode 1 and to the anode 2 with a voltage applied, which leads to a breakdown through the conductive film on the surface of the insulator 4 dividing the surface 5 of the cathode 1 from the anode 2, and excitation of the vacuum arc. The cathode spot formed during arc burning on the surface 5 causes the cathode 1 material to evaporate. A plasma of the cathode material is formed in the arc, which is focused into the plasma jet 10 and accelerated by the magnetic coil 3 due to the action of electromagnetic force on the plasma. Part of the vapor of the cathode material is deposited on the surface of the insulator 4 and "restores" the conductive film on it. After passing the arc current through zero, the arc goes out and the device is again ready for operation. After a time interval of 2%, the signal from the control unit 9 is supplied to the controlled valve 7 of the next phase, the voltage of which at this time point is maxi4

At a minimum, the valve opens, a breakdown occurs along the production film on the surface of the insulator 4, a vacuum arc is excited between electrodes 1 and 2, and the whole cycle repeats. Thus, during the period of alternating voltage, t ⁵ times the excitation and extinction of the arc occurs, the plasma of the cathode material is generated t times. The evaporation rate is regulated by the control unit 9, which allows you to change both the angle and the frequency from ₁₀ covered groups of t-controlled valves 7, thereby 'adjust the average value

 arc current.

The device was used as a pulsed sublimator for evaporation of titanium in a sorption vacuum pump, which was powered from a two-phase current with a frequency of 50 Hz according to the scheme shown in FIG. 1. The following parameters were obtained: regulation range, titanium evaporation rates from 10 ~ ^a to 30 g / h,

_20, which corresponds to a regulation depth of 3000; the maximum power consumed from the mains, 3 kW at a phase voltage of 120 V, the pumping time of the technological volume of the vacuum deposition unit of the UWI type — 2M — 2 from the fore vacuum vacuum pressure

25 54 O ' ^a mmHg Art. to a pressure of 1-10 mm Hg 15-18 min.

Claims (1)

Claim ³⁰ A device for arc evaporation in vacuum, containing two electrodes, one of which is made of evaporating material for movement, a magnetic coil, an insulator separating the working surface of the electrodes, a multiphase power source with a transformer, characterized in that, in order to increase the range of regulation evaporation rate, one of the electrodes is connected to a multiphase power transformer Nia pit ⁴⁰ through a group of controlled rectifiers, while the other is connected to the zero terminal of said Transfrm Ator.