SU1343338A1 - Measuring device - Google Patents

Abstract

The invention relates to a measurement technique and allows the automation of the measurement of the ion saturation current and the temperature of the plasma electrons. The linearly varying signal from the generator 1, the linearly varying voltage is applied to the electric probe 21. Differential amplifiers 6 and 8 amplify signals proportional to the ion and resulting plasma currents, the differential amplifier 7 produces a signal proportional to the electron current of the plasma, further this signal logarithm (block 10), differentiated (block 11), scaled (block I2) and transmitted to the recorder 22, where two values are displayed: the ion saturation current and the temperature of the plasma electrons, 1 and . with F (L with: DO 4 00 CO 00 00

Description

The invention relates to methods for measuring plasma parameters, in particular for determining the ionic saturation current and temperature of electrons in diagnostics and decision making in low-temperature plasma control processes, and can be used to control technological processes in the manufacture of integrated circuits, as well as in experimental physics for conducting experiments with low-temperature plasma.

The purpose of the invention is to expand the class of problems to be solved by determining the ion saturation current and the temperature of the plasma electrons.

The drawing shows a functional diagram of the proposed device.

The device contains a generator of linearly varying voltage, the first 2 and second 3 diodes, the first 4 and second 5 resistors, the first differential amplifier 6, the third differential 1 × 7 amplifier, the second differential amplifier 8, the first memory block 9, a plasma electron temperature calculator 10 comprising a logarithmic unit 11, a differentiation unit 12 and a scaling unit 13.

In addition, the device contains the second memory block 14, the first 15 and the second 16 double-threshold comparators, the inputs for setting the first and second thresholds of which are connected via the corresponding inputs of the measurement mode setting of the device to the reference voltage sources 17-20.

The information input of the device is connected to the electrical probe 21. The outputs of the plasma saturation ion current values and the plasma electron temperature of the device can be connected to the recorder 22.

The measurement is based on a known method. At the first stage, probes 1 of the volt-ampere plasma characteristic are measured using measuring instruments. To do this, a certain potential difference is introduced between the probe and the reference electrode, the magnitude and polarity of which can be changed by a regulating source consisting of a voltage source and a rheostat.

Measurements begin by fixing and then memorizing

ion tick saturation 1. Then, the measured value of I is subtracted from the total current of the probe Ip and the values of the electron plasma current Ig are obtained as a function of the potential difference between the probe and the reference electrode. After that, plotting is made on a logarithmic scale of graph I, f (U), where and is the potential difference between the probe and the reference electrode. The slope of the curve of this graph in the region VP: O is determined by the equations and V. + V,

 e

SP

t

R

.eVp. po exp ().

 1п1, „,

0

five

0

five

where v

potential difference between the reference electrode and the space charge layer; potential of the probe surface with respect to the boundary of the spatial charge layer;

plasma electron current;

electron current; constant Boltzmann; electron charge; electron temperature, If electrons have a Maxwell distribution, then the slope is constant and gives the plasma electron temperature

SP

Have „IEO

IE k

e

TO

dlnl dlnle e dU

T

eight

Vp.O;

T. b

dlnlf

40

45

50

The device works as follows.

The linearly varying signal from generator 1 through the first 2 and second 3 diodes, the first 4 and second 5 resistors is connected to the electrical probe 21. On the first 2 and second 3 diodes, the total current and its ion component are separated, and the first 4 and The second 5 resistors, signals proportional to the plasma saturation ion current and the resulting current of the electric probe 21, respectively, receive 55 to the second 8 and first 6 differential amplifiers. From the output of the second differential amplifier 8, the signal corresponding to the plasma ionic current is fed to the receiver.

formanion flow of memory block 9. The operation of block 9 is controlled by a two-line comparator 15, which at the present moment produces a massive impulse supplied to the input of sample 5 of block 9, where the value of the analog value is fixed. To fix the value in block 9, corresponding to: the total ion current value of the 1st 1st plasma, it is necessary to adjust the source of NICKY 17 and 18 in such a way that

0 and; -, 7 and, p, and „(- J U --- II

where 0.7 and and.

g

- Nakr zhsni on sources 17 and 18 of the reference voltage, respectively. Of course i

dU - goal, determined by the yu lppslssnost uprshshchuyuschy pulse.

The moment f1tk: a,., Ich of the parameter, corresponding to the ion saturation current, in memory block 9 must be selected when a linearly varying signal produced by the generator 1 reaches its minimum. The two-threshold comparator 16 works in a similar way.

The setting of sources I9 and 20 of the operating voltage is made in such a way that

О U, g and ,,, and „+., J, where U, g and and are voltages at sources 19 and 20, respectively;

dU is the value that determines the duration of the control pulse.

The moment of fixation of the parameter corresponding to the temperature of the plasma electrons must be chosen when it reaches a linearly varying signal produced by generator 1,

zero value. From the output of memory block 9, the signal goes to the non-inverting input of the third differential amplifier 7 and to the first input of the recorder 22. The inverting input of the third differential amplifier 7 receives a signal from the output of the first differential amplifier 6, corresponding to the total current of probe 21. The differential signal from the output of the third differential amplifier 7, which determines the plasma current, is fed to the input of the logarithmic unit 11, where the function is calculated electron current in logarithmic mas34

1 hg1 t output of block 1 logarithm-;) o: the signal is fed to the input of block 12 of differentiation, where the differential of the function of the logarithm of the electron current is calculated by the potential of the probe's distortion with respect to the spatial charge boundary V. From the output of block 12, the signal to the block 13, in which the signal is multiplied by 1 time k / e, where k is constant} {by Bopnman, e is the charge of the tctron.

After block 13, the signal is sent to the informational digital input of block 14 memory,, p (|) T1, the value of the temperature of the electron is measured at the moment-ii, riis, when a huge change of power is achieved; nalenog values. From the out of the third ,,; about 14 memory, the signal is received i: a iviopo device 22 input. Obviously, device 22 can display priK ;: i bottom. lgins; ion current on g. and TCMiit riaT yps electrons

1- / J; we.

 i p m u l a i: j about meeting () 1tgep l se ustrokszo сод content uYUS, :: DIfer; HUAaJ GOD HAS POWERED

 ii.j two blocks of Ps mti and generator of l .-. change of variance of Ю111degsg 11-1 ч, 1 l and h and m of e with the fact that, with Л: 11:; .. 1 ; och due to ion ore deflection} {ac; -G1 (i.i. electro-temperature): ./: apasms, two two 1K 1 OG sun x comparators, the second and three 111 differential, iRFR, two renistors , two diodes and a tag transmitter; plasma electrons, the output of the detector is measured, its voltage is applied to: the information inputs of the first and second two-way diodes, to the cathode of the first diode and to the ano /; in the ivroporo diode, the anode of the first and cathope of the second diode connectors: s to inveg tpr-t.ttsm inputs of the second and dirtieth differential amplifiers; it is different both through the top and the po: -: HC iri;, bi - respectively, to the ICF forms, to the device input and to the unqualified qi (the inputs of the first and first amplifiers, which are connected to an inverting input third differential v; l -: tr. i4 and with HHdsop513433386

memory input of the first memory block, the output of which

respectively, the output of which is the output of the temperature value is the output of the ion-current value of the electrons of the plasma of the device, entering plasma saturation with devices to sample the first and second blocks

dinene with non-inverting input third-5th tees are connected to the outputs of the first

its differential amplifier, you and the second two-threshold comparators

the course of which is connected to information, respectively, the inputs of setting the first input of the calculator of temperature and the second thresholds of which are plasma electrons, the output of which is the input of setting the measurement mode

connected to the inormament input of the second device.

Claims (1)

Iseler’s entire device, the contents of the first differential force | g, two memory blocks and a generator a., Of a secretly varying voltage, say that it’s purpose ;. ' the expansion of the class of problems to be solved by determining the ionic saturation current r of the plasma electron temperature, two two-threshold comparators, the second and third differential amplifiers, two resistors, two diodes and a plasma electron temperature calculator are introduced into it, the output of the ramp generator is connected to information inputs the first and second two-threshold co-op, to the cathode of the first diode and to the anode of the second diode, the anode of the first and the cathode of the second diode are connected to the investment inputs of the second and first differential of differential amplifiers, respectively, and through the first and r-game, the resonators, respectively, to the information / input of the device and to the non-inverting inputs of the first and second differential amplifiers, the outputs of which are connected to the inverting input of the third differential unit. memory, the output of which is the output 5 memory are connected to the outputs of the first and second two-threshold comparators, respectively, the inputs of the job of the first and second thresholds of which are inputs of the job of the measurement mode of the device. the input of the first memory block, respectively, whose output is the output of the value of the saturation ion current of the plasma of the device and is connected to the non-inverting input of the third differential amplifier, the output of which is connected to the information input of the plasma electron temperature calculator, the output of which is connected to the information input of the second-> 0