SU924621A1 - Device for measuring non-linear element parameters - Google Patents

Description

The invention relates to a radio metering technique, is intended to measure the total conductivities and quality factors of various linear and nonlinear elements with increased accuracy over a wide range of operating frequencies and can be used for process control of parameters of semiconductor devices and other objects with unfavorable ratios of the components of total conductivities.

A device for measuring the quality factor and capacitance of semiconductor devices is known, based on compensation of active losses in the measuring unit during its shock excitation and containing a generator of trigger pulses, a control unit, a limiting amplifier of different polarity pulses, a comparison and indicator blocks, an analog divider, as well as the element under study with a source and a bias voltage meter and controlled exemplary negative active and reactive conductivities 1.

The specified device is capable of operating at higher frequencies, however

it does not provide the necessary accuracy and speed measurements.

It is also known a device for measuring the total conductivities and good quality of nonlinear elements, comprising a trigger pulse generator, a control unit connected to the input of the measuring unit, differentiating and comparing blocks, an amplifier-limiter, an analog divider, an indicator unit, a source. and a bias voltage meter, controlled exemplary active and reactive conductivities, as well as an extremum detection unit, a switch, two synchronous demodulators, RS and T triggers, two AND elements, an NOT element, an OR element, and an integrator. The principle of operation of the device is based on the formation and modulation by switching the investigated element in the measuring unit of shock-excited quarter-wave oscillations with subsequent analysis of their amplitude and period, as well as full compensation of the measured parameters by negative components of exemplary conductivities 2.

The known device has an increased speed and is designed to work in the field of relatively low frequencies. Due to the frequency limitation due to the limited resolution of the comparing unit and the integrator, it is impossible with the required degree of accuracy to perform the Uranon-hanging of the autocompensation systems of the active and reactive components in the measuring unit of the device, which sharply reduces the accuracy of measurements of the parameters of nonlinear elements. The purpose of the invention is to improve the measurement accuracy and expand the frequency range of the device. To achieve this goal, a device for measuring parameters of nonlinear elements, containing a control unit connected to the input of the measuring unit, an extremum recording unit connected to the first output of the measuring unit, differentiating and comparing blocks, integrator, analogue divider, the first and second inputs of which are connected respectively, to the outputs of the comparing unit and the integrator, a switch, the information input of which is connected to the second output of the measuring unit, two elements AND, a the ENT element, the OR element, the RS flip-flop, the output of which is connected to the input of the control unit, the T-flip-flop of the direct output of which is connected to the control input of the switch and one of the inputs of the first element AND, and the inverse one - with one of the inputs of the second element AND, two synchronous demodulators, the control inputs of which are respectively connected to the outputs of the first and second elements AND, and the outputs with the corresponding inputs of the comparison unit, a generator of trigger pulses connected to the T-trigger setup input and one. from the inputs of the first element OR, the source of the bias voltage, connected to one of the terminals for connecting the investigated nonlinear element, the indicator unit, the separate inputs of which are connected respectively to the outputs of the integrator, the matching unit, the analog divider and the source of the bias voltage, as well as controlled reference active and re-active conductivity, some of the conclusions of which, together with the output of the switch, are connected to another terminal for connecting the test linear element, the other conclusions are with a common t device, and the control inputs of the controlled exemplary active conductivity, respectively, with the outputs of the comparison unit and the controlled exemplary reactive conductivity with the integrator output, the comparator, the BAN element, the second OR element, the third AND digital element of the delay, the second RS flip-flop and frequency divider with a variable division factor, one of the inputs of the comparator is connected to the common point of the device, the second to the first output of the measuring unit, and the output to one of the inputs of the third element And, another input of which is connected to the output of the extremum registration unit, the output of the third element AND is connected directly to the counting input of a frequency divider with a variable division factor and through the element NOT to one of the inputs of the second element OR, the setting input of a frequency divider with a variable division factor and the second the input of the OR element is connected to the output of the trigger pulse generator, and their outputs are connected respectively to the S and R inputs of the second RS flip-flop, the direct output of which is connected directly to other the inputs of the first and second elements are And, and the inverse through a differentiating unit is connected to the direct input of the BANNER element, the inverse input of which is connected to the output of the trigger pulse generator, and the output to the counting input of the T-flip-flop and the other input of the first OR element, whose output is directly connected to R-input and through a digital delay element with the S-input of the first RS-flip-flop, while the integrator inputs are connected to the corresponding T-flip-flop outputs and the information inputs of both synchronous demodulators are connected to the first At the exit of the measuring unit. Figure 1 shows a block diagram of a device for measuring parameters of nonlinear elements; in fig. 2 - diagrams, explaining the principle of measurement and operation of the device. A device for measuring the parameters of nonlinear elements contains measuring unit 1 to which the switchable nonlinear element 3 with the source 4 of the bias voltage is connected via switch 2, with which the measurement of the studied nonlinear element 3 is required. The vibration is excited in measuring unit 1 using the system, which includes an extremum registration unit 5, comparator 6, the third element. And 7, element 8, second element-OR 9, divider 10 frequency with variable division factor, second RS-flip-flop 11, differentiating block 12, element BAN 13, first-element OR 14, digital delay element 15, first RS-trigger 16 and block 17 controls In this device, the extremum detection unit 5 is bipolar. The T-flip-flop 18 controls switch 2 and generates information about the oscillation periods in measuring unit 1 for a channel measuring the reactive component of the conductivity of the elements under study, which include integrator 19 and controlled sample reactive conductivity 20, V analyzing information about the amplitudes of the oscillations in the measuring unit 1, the first and second synchronous demodulators 21 and 22 are included, comparing the unit 23 and the controllable sample of the active conductivity 24 24 l emye active and reactive 20 made negative conductance. Analog divider 25 provides a direct reading of the quality factor of the nonlinear elements under study. The measurement channel of the active conductivity component is synchronized by pulses formed at the outputs of the first and second elements 26 and 27. The initial conditions of operation of the entire device are provided by the generator 28 trigger pulses, and the registration of all measured parameters, including the bias voltage of the element under study, carried out using the indicator unit 29.

The device works as follows.

We shall follow the dynamics of the processes occurring in the device from the time when the initial conditions for the operation of individual units are established. However, regardless of the state of the latter, a relatively short rectangular pulse (Fig. 2a) of the trigger pulse generator 28 through the element OR 14 acts on the R input of the first RS trigger 16 and sets it to the initial (zero) state at which the block Control 17 shunts measuring unit 1 and oscillations in it. are missing. Simultaneously, the pulse of the generator 28 triggering pulses, acting directly on the installation inputs of the splitter 1Q frequency with a variable division factor and T-trigger 18 and through the element OR 9 on the R-input of the second RS-trigger 11, fixes the latter in the initial states. The same impulse, falling on the inverse input of the BANCH element 13, prevents for the duration of its duration the appearance at its output of any pulses formed, for example, as a result of switching the second RS trigger 11 and subsequent processing in the differentiating unit 12, which eliminates false triggering T -trigger 18, and later on, and the first RS flip-flop 16. There is a low potential at the direct output T-trigger-.

Hera 18 opens the switch 2 and prevents the appearance of a pulse at the output of the first element And 26, and the high potential acting on the inverse output contributes to the formation of that at the output of the second element And 27, however, at this time, because of. There is a low potential in the direct output of the second RS flip-flop 11, this pulse is absent. The existing high potential at the inverse output of the T-flip-flop 18 is also fed to one of the inputs of the integrator 19, where the time is the amplitude-conversion.

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After the time interval St, which is determined by the time of establishing transients occurring in the device, expires, a delayed pulse (Fig. 26) of the trigger pulse generator 28 appears at the output of the digital delay element 15, which affects the Z input of the first RS flip-flop 16 translates it into a single state (phi;; 2c), which causes control unit 17 to cause shock excitation of oscillations (FIG. 2d) in measuring unit 1. The resulting oscillations with a certain initial phase, for example, such as shown in FIG. 2g subjected to conversion in the extremum detection unit 5 and the comparator 6, and also received for analysis to the information inputs of synchronous demodulators 21 and 22. The comparator 6 generates rectangular pulses (FIG. 2d), the phases of which correspond to the transition of the initial oscillation (FIG. ) through zero (one input of the comparator 6 is connected to the common point of the device), and block 5

The registration of the extremum is similar to the pulses (Fig. 2e), the phases of which correspond to the location of the extreme points on this oscillation. The pulses formed in block 5 of the registration of the extremum and the comparator 6 blunt on separate inputs of the third element I 7, where they interact with each other, form rectangular pulses (Fig. 2g), the duration and location of which exactly COOT0 correspond to the intervals of time between the first crossing through zero and the extremum of each positive half-wave of shock-excited oscillations (FIG. 2d).

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The received pulses, inverting the HE element 8 and the passage through the OR 9 element, do not cause a change in the state of the second RS flip-flop 11 until a pulse is formed at the output of the frequency divider 10 with a variable division factor, the analyzing impulses. The occurrence in time of a pulse at the output of a divider 10 frequency with a variable coefficient

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depends on the set division factor n, the value of which can vary over a wide range, reaching several tens or hundreds of units. Due to the fact that the accepted numerical value of the division factor n does not fundamentally affect the dynamics of the processes taking place, let us consider the operation of the device with (this case is shown in Fig. 2).

In this situation, at the moment of the formation of the third period of the shock-induced oscillation (fig.2g), which corresponds to the beginning of the third pulse (fig.2g) acting on the output of the third element And 7, a short pulse appears (fig.2z) divider 10 frequencies with a variable division factor, which acts on the S input of the second RS flip-flop 11 and puts the latter into one state. A high potential acquired at the direct output of this RS flip-flop 11 (FIG. 2i) passes to the output of the second And element 27 (fig.2k) and opens for receiving information and the second synchronous modulator 22. This synchronous modulator 22, which produces continuous tracking and memorization, perceives at a given moment of time information about the amplitude of the third period of the shock-excited oscillation (shaded area in Fig. 2d) acting on the first output of the measuring unit 1. Acquired during the considered time intervals, the information is converted in the integrator 19 and the second synchronous demodulator 22 to a voltage of a certain polarity. These voltages, acting separately (the first directly, and the second through the comparison block 23) to the control inputs of the controlled reactive model 20 and active 24 conductances, displace them under the influence of a large difference signal (compensating for the voltage of the second inputs of the integrator 19 and comparing block 23 are missing) in the direction of large values of negative conductivities

Upon reaching the maximum amplitude of the third oscillation period Upn (FIG. 2d), the formation of the extremum and comparator 6 of the third pulse at the output of the third element And 7 is completed using the block 5, registering the extremum. This pulse (FIG. 2g), inverted in the element HE 8 and passed the element OR 9, the falling edge returns to the initial state the second RS flip-flop 11 (Fig. 2i). The disappearance of a high potential at the direct output of this trigger eliminates the control pulse at the output of the element 27 (fig. 2k), which puts the second synchronous demodulator 22 in the storage mode of the accumulated information on the maximum amplitude of the oscillation uj, (fig. 2d). The high potential at the inverse output of the second RS flip-flop 11, processed in the differentiating unit 12, forms at the output of the last a sharp-pointed impulse (FIG. 2L), which through an open element BAN, 13 (the inhibiting signal on the inverting input of the element in this the moment of time is absent) acts directly on the counting input of the T-flip-flop 18 and through the first element OR 14 to the .R-input of the first RS-flip-flop 16 and overturns them. In this case, the control unit 17, obtaining a low potential (Fig. 2 from the output of the first RS flip-flop 16, shunts the measuring unit 1 and the oscillatory process in it, rapidly decaying exponentially, stops, completing the formation of a series of shock-excited oscillations with a period Td (Fig. 2d), corresponding to the actual resonant frequency of the measuring unit 1. The arising high potential (Fig. 2m) at the forward output of the Thrigger 18 switches the switch 2 to a closed state and thus connects the controlled active active 24 and reactive 20 conductivity and, when measured, the investigated nonlinear element 3 with the source 4 of the bias voltage to the measuring unit 1. At the same time, the same potential prepares the first element AND 26 for receiving information and is fed for processing to the second input of the integrator 19. By this time In the integrator 19, information on the period T of a series of shock-excited oscillations accumulates in the form of a voltage of a certain polarity (Fig. 2d), which is concentrated in the duration of the pulse that existed in the inverse output of the T-flip-flop 18.

After a delay time Cj (Fig. 2L), a short pulse occurs at the output of the digital delay element 15 (Fig. 26), which previously operated at the output of differentiating unit 12. This pulse goes to the S input of the first RS flip-flop 16, which again goes to the unit state (Fig. 2c), by means of the control block 17, again causes the shock excitation of oscillations in the measuring block 1. As a new series of shock-excited oscillations is formed (Fig. 2d) with a smaller amplitude damping decrement and a shortened period due to the fact that negative and active and reactive conductivity are introduced into measuring unit 1, information about the current oscillation period continuously coming from the direct output T-flip-flop 18 to the second input of the integrator 19, compensates for the previously accumulated information about

the initial period Td and shifts the controlled exemplary reactive conductivity 20 in the direction of smaller values of the negative component, contributing to an increase in the oscillation period.

At the same time, the resulting new series of shock-excited oscillations, subjected to the above processing in the extremum registration unit 5 (Fig. 2e), the comparator 6 (Fig. 2d) and the third element And 7, forms a sequence of square impulses (Fig. 2g) , the temporary position of each pulse of which corresponds to the location of the first quarters of positive half-waves of the analyzed oscillations. This sequence of pulses acts through the element HE 8 and the second element OR 9 on the R input of the second RS flip-flop 11, without causing a change in the state of the latter, and on the counting input of the | Tel 10 frequency with a variable division factor. Upon receipt of the required number of pulses corresponding to the previously established division factor, a short pulse (Fig. 2h) appears at the output of the frequency divider 10 with a variable division factor, under the influence of which the second RS flip-flop returns to the unit state again. The generated single signal at the direct output of this trigger (Fig. 2i) is fed through the first element AND 26 to the control input of the first synchronous demodulator 21 and opens the latter for receiving information. Coming from the first output of the measuring unit 1, information about the current amplitude of the third period of the shock-excited oscillation (shaded area in Fig. 2d), continuously accumulating in the first synchronous demodulator 21, overcomes the information stored by the second demodulator 22 and displaces the controlled sample active conductivity 24 in the direction of smaller values of the negative component, restraining the relative increase in the amplitude of oscillations.

As a result of the noted oppositions occurring in integrator 19 and comparing unit 23, it is not likely that even by the time the formation of this series of shock-excited oscillations was completed, their amplitude and period coincided with the initial ones. It should be noted that the presence of negative feedback in the active and reactive component balancing circuits, the depth of which in the initial period of equilibration of the device is the most non-constant in time leads to a violation of the constant of the amplitude attenuation and oscillation period within the limits of

This series. In the future, as the device approaches the balanced state by forming subsequent series of shock-excited oscillations, the marked nonlinear dependence practically disappears.

Thus, the cases where the amplitude and oscillation period at the end of the series being formed are not equal to Uon and Td are the most likely, and they can be both more and less than they all depend on the inertia of the balance contours along the active and reactive components, as well as on whether or not the measuring element 3 is connected to the measuring unit 1, taking into account the nature of its total conductivities. Regardless of which of the cases prevails at a given time, it is not decisive for the dynamics of the processes occurring in the device.

Let by the moment of the end of the formation of this series the shock-excited oscillations are characterized by the amplitude Jgr, and the period T TO, while reaching the maximum amplitudes. The third oscillation period (Fig. 2d) ends with the method described above, the formation of the third pulse (Fig. 2g) at the output of the third element And 7, the falling front of which, in the manner described above, returns to the initial state one after the other RS-trigger 11, T the trigger 18 with the first RS trigger 16 and the control block 17, which, to shunt the measuring unit, stops the oscillatory process in it. The disappearance of a high potential (Fig. 2i) at the direct output of the second RS flip-flop 11 completes the formation of a control pulse (Fig. 2n) at the output of the first element 26, which converts the first synchronous demodulator 21 into the storage mode of the accumulated information about the amplitude maximum U -in, and the appearance of a low potential (Fig. 2m) at the direct output of the T-flip-flop 18 drives switch 2 to the open state, disconnecting the controlled exemplary active 24 and reactive 20 conductivities from the measuring unit 1, and stops the input to the second input int The supporter 19 of information about the period T of the current oscillation.

Subsequently, the processes of oscillation formation in the measuring unit 1 and the separation of information about the component amplitudes and periods of these oscillations are periodically repeated, creating continuously incoming information about the amplitude Ugp and period T (j exemplary oscillations that make up the own parameters of the measuring circuit 1) in the second synchronous the demodulator 22 and one of the inputs of the integrator 19, and the information of the cGE amplitude and period of oscillations, depending on the state of time controlled by the model active 24 and p active 20 and the nature of the measured components of the investigated element 3, - into the first dehydulator 21 and, alternatively, with the integrator 13 As a result of continuous comparison of the output from the output of the first synchronous demodulator 21 and pulse durations from the direct output of the T-trigger 18 to the reference level the signal from the output of the second synchronous demodulator 22 and the duration of the sample pulses from the inverse output of the T-flip-flop 18, respectively, in the comparison block 23 and the integrator 19, differential signals are formed, which tend to change the control state separately L x active 24 and reactive 20 conductivities so that the excited oscillations bring them closer to exemplary and, bring the amplitude and period stabilization systems / s to a balanced state regardless of whether or not the controlled active 20 are connected or not connected to the measuring unit 1 I-active 20 conductors and the nonlinear element under study 3.

The approximation of shock-excited oscillations to the exemplary ones within the formed series becomes possible due to the fact that when the device is equilibrated by the reactive component, regardless of the state of switch 2, the measuring unit acquires the same value of wave resistance, the magnitude of which, as we know, depends on the initial height of shock of the excited oscillations U (Fig. 2d), Therefore, if during the time of action of two successive series of shock-excited oscillations, the parameters of the control unit will not not easily modified in practice, the initial amplitudes of the oscillations formed will be equal. Therefore, it is sufficient to analyze only the amplitudes at the end of the formed series of oscillations, not paying attention to the behavior of the initial amplitudes in the process of load balancing the device. when doing U1SLOVY and

the corresponding amplitudes of the shock excitations will be uniquely equal. fluctuations of the formed series, for example, and UQ., (fig.Zg) and t, d.

In this way, after 3-4 full cycles of excitation of oscillations of the system; . :: -. ; .::; ik uramnovyvayutsya with. -. :: m clavieHbio accuracy and in the distance:; imeg; globalized tracking of out; ,.;,:, M, i; e; ,,., G parameters of the studied C; vi: ii a 3; for example, by means of a displacement of the source 4 or other disturbing factors. fully compensating for the Sr-1r em1le components of the conductivity of the corresponding negative components of the controlled exemplary arg; type 24 and reactive 20 conductivities. Under such conditions, the control voltage of the controllable specimens and the active 24 and reactive 20 conductances are proportional to the total full conductance and are fed to the indicator unit 29 for registration, as well as to the corresponding notes of the tax indicator. 25 to calculate the quality of the test element 3 and then register it.

The proposed device, as compared with the known one, is advantageously distinguished by an increased measurement accuracy and a wide frequency range of operation.

F with rm la inventions

} / StroboTBO for measuring the parameters of nonlinear elements, containing a control unit connected to the input of the measuring unit, register unit: L1I extremum-a, connected to the first 5y 31; 1 output of the measuring unit,, diPfere; -; 1; I compare the blocks, the integrator, the analog divider, the first and the second of which are under KJi: C4eH ii respectively to the outputs of the comparison block and the integrator, a switch whose information input is connected to the second / iy output of the measuring block, two elements AND, element NOT, element OR , RS trigger, output to-t The ogo is connected to the control 1M input of the switch and one of the inputs of the first element AND, and the inverse one with one of the inputs of the second element AND, two synchronous divisions-5 modules, the control inputs of which are respectively connected to you; -; And, and exits - with the appropriate fa; the inputs of the comparing unit, the switching pulses, the adjusting input Ti, one of the inputs of the first, the voltage source connected to one of the connected nonlinear elementary test indicator, whose p-inputs are connected respectively to the outputs of the integrator, the comparing unit, the analog divider and source of bias voltage, as well as controlled exemplary active and reactive conductivities, some of the outputs of which, together with the output of the switch, are connected to another clamp for. connecting the test element, the other outputs are with a common point of the device, and the control inputs of the controlled exemplary active conductivity correspond respectively to the outputs of the comparison unit and the controlled exemplary reactive conductivity with the integrator output, characterized in that, in order to improve the accuracy of measurements and expand the frequency range of the device, it introduced a comparator, the element BAN, the second element OR, the third element AND, the digital delay element, the second RS-flip-flop and a frequency divider with variable coefficient The division of the division, and one of the inputs of the comparator is connected to the common point of the device, the second - to the first output of the measuring unit, and the output to one of the inputs of the third element, the other input of which is connected to the output of the extremum recording unit, the output of the third element And is connected directly to the counting input the element and through the element NOT with one of the inputs of the second element OR, the setting input of the frequency divider with variable division factor and

the second input element OR is connected to the output of the trigger pulse generator, and their outputs are connected respectively to the S and R inputs of the second RS flip-flop, the direct output of which 5 is connected directly to the other inputs of the first and second elements AND, and the inverse through the differentiating unit is connected with the direct input of the BANCH element, the inverse input of which is connected to the output of the trigger pulse generator, and the output with the counting input of the T-flip-flop and another input of the first OR element, the output of which is directly connected

with the R input and through the digital delay element with the S input of the first RS flip-flop, the integrator inputs are connected to the corresponding T-flip-flop outputs, and the information inputs of both synchronous demodulators

U connected to the first output of the measuring unit.

Sources of information taken into account in the examination of 5 USSR author's certificate. 429375, cl. G 01 R 27/26, published. 02.07.75.

2. USSR author's certificate 691781, cl. G 01 R 27/26, .. G 01 R 27/00, published. 10/18/79 (prototype).

Claims (1)

Fsrmula. inventions A device for measuring the parameters of nonlinear elements, comprising a control unit, connections to the input of the measuring unit, an extremum registration unit connected to the first output of the measuring unit, differentiating and comparing units, an integrator, an analog divider, the first and second inputs of which are connected respectively to the outputs of the comparing unit and an integrator, a switch, the information input of which is connected to the second output of the measuring unit, two AND elements, an NOT element, an OR element, an RS trigger, direct output for which it is connected to the control input of the switch and one of the inputs of the first element And, and the inverse - to one of the inputs of the second element And, two synchronous demodulators, the control inputs of which are respectively connected to the outputs of the first and second elements And, and the outputs - with the corresponding inputs of the unit, a trigger pulse generator connected to the Trigger installation input and one of the inputs of the first OR element, a bias voltage source connected to one of the terminals for connecting the nonlinear of the * element is an indicator unit, the separate inputs of which are connected respectively to the outputs of the integrator, the comparison unit, the analog divider and the bias voltage source, as well as the controlled reference active and reactive conductivities, some of whose outputs together with the switch output are connected to another terminal for connection of the element under study, other conclusions - with a common point of the device, and the control inputs of the controlled model active conductivity - respectively, with the outputs of the comparison unit and control образ exemplary reactive conductivity with an integrator output, characterized in that, in order to increase the accuracy of measurements and extend the frequency range of the device, a comparator, a BAN element, a second OR element, a third AND element, a digital delay element, a second RS-trigger and a frequency divider with a variable division coefficient, one of the inputs of the comparator connected to a common point of the device, the second to the first output of the measuring unit, and the output to one of the inputs of the third element And, the other input of which It is connected to the output of the extremum registration unit, the output of the third AND element is connected directly to the counting input of the divider and through the NOT element to one of the inputs of the second OR element, the installation input of the frequency divider with a variable division coefficient and the second input of the OR element is connected to the output of the trigger pulse generator, and their outputs are connected respectively to the S- and R-inputs of the second RS-flip-flop, the direct output of which 5 is connected directly to other inputs of the first and second elements And, and the inverse through a differentiating block connected to the direct input of the BAN element, the inverse input of which is 10 connected to the output of the trigger pulse generator, and the output is with the counting input of the T-trigger and the other input of the first OR element, the output of which is connected directly to the R-input and through the digital '5 delay element with S -input of the first RS-trigger, while the integrator inputs are connected to the corresponding outputs of the T-trigger, and the information inputs of both synchronous demodulators 20 are connected to the first output of the measuring unit.