JPS6082977A - Semiconductor element characteristic measuring device - Google Patents

Abstract

PURPOSE:To measure in a short time the detailed frequency characteristic of a high frequency element by a simplified device, by using a high frequency generator which oscillation frequency varies uniformly as a time elapses. CONSTITUTION:A signal generator 11 is prescribed exactly by a hardware with regard to the upper limit and the lower limit of an oscillation frequency, and generates a signal which has varied uniformly the oscillation frequency as a time elapses. Also, a network analyzer 14 is synchronized with an oscillating signal of the signal generator 11, and detects input and output signals to an element to be measured 15 connected to a DC bias power source 16. Subsequently, which regard to all bands of the frequency which can be measured by a measuring device, the inside of the band is divided by a measuring resolution which the network analyzer 14 has, an S parameter of each frequency is measured by one sweep of the oscillating signal of the signal generator, and only the measured value of a necessary frequency is outputted to an external device from the network analyzer 14.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to a single-frequency measurement device for semiconductor devices.

The electrical characteristics of a semiconductor device can be expressed using various parameters, assuming that the semiconductor device is a 4-port black box as shown in FIG. Parameters often used at this time include H, Y, and 2 parameters. These are parameters that relate the total voltage and total current, which are circuit variables of each boat.

H parameter Vs =hs IL 1h1w I2゛~l gate =h□ 11 +httIz ・・・・・・(
1-Y parameter E+ = Ys IVH+y, t
v.

I, =y, IV, -)y22 V,...
(2) Z harameter Vt = Z11 s It -1
−z, g I2Vt =Zx IIs +Zz t
I2 (3) The difference between these parameters is the difference between an independent variable and a dependent variable, and each parameter is nothing but a constant that relates these variables.

A method for measuring this type of parameter will be explained using the H parameter as an example. hll is determined by setting the voltage v2 at the output to zero, ie by short-circuiting the output of the network. hll is the ratio of the voltage 1 at the input end to the current 2 at the input end, that is, the input impedance of the circuit. htt is the voltage v1 at the input end when the input end is open
From K, it is important to measure the ratio of the voltage v2 at the output terminal, that is, the reverse voltage gain. The basic conditions for this measurement are open conditions and short circuit conditions.

However, as the frequency increases, various problems arise, including the two conditions mentioned above.

1. ′ of the total voltage and total current at the network terminals
Direct continuation is not possible.

2. It is difficult to obtain open and short circuit conditions over a wide band.

3. Active devices such as semiconductor devices may become unstable due to short circuits or open circuits.

For higher frequencies, new measurement methods are needed. As shown in Figure 2, a 4-port element is inserted on a high-frequency transmission line, the transmission line is terminated with a characteristic impedance of 7, and an input signal is applied to the semiconductor element from a signal source 9 with an impedance of 8. For input signals, reflected signals, and transmitted signals, the input and output terminals are expressed in terms of power as shown below.

E, r=s, 1E, i+S, PJ2i” ”” ”
1 l+% Karasu t bl =811 al +Su a.

b2=82+ a+ +8n a2 ...--(4)
ZO: Line characteristic impedance 'Enr: Reflected voltage at input and output terminals lni: Incident voltage For example, considering S++ in equation (4), the incident power on the output terminal side is set to zero, and the reflected power on the input terminal side is input. Consider the power ratio. In other words, this can be achieved by connecting a load equal to the characteristic impedance to the output end.

When measuring the high frequency characteristics of the input and output of elements on a high frequency transmission line using S parameters.

Compared to measurements of other parameters, it has the following advantages:

1. Since a resistance value equal to the characteristic impedance is used, H,
Open and short conditions during Y and Z parameter measurements are not required.

2. Since the measurement always involves a load, unstable states of active elements can be eliminated.

3. Each signal can be handled with electric power at the input and output.

From the above, S-parameters are generally used to indicate the electrical characteristics of high-frequency semiconductor elements and components.

Figure 3 shows a 7-stem block diagram of an 8-parameter measuring device for high-frequency semiconductor devices.
The high frequency signal generated from the
, the high frequency signal is controlled to a predetermined frequency. The other signal shunted by the signal shunt 2 is applied to the transistor under test 5 via the network analyzer 4.

A circuit is configured with the measurement state of each S parameter and the network analyzer 4, and the high frequency characteristics of the element are measured.

Frequency characteristics are often required when displaying the characteristics of high-frequency semiconductor devices, and when using conventional measurement methods, as the number of measurement frequencies increases, frequency settings must be performed sequentially for each frequency and each parameter measurement. -The measurement time was extremely long, making it unsuitable as a device for measuring detailed frequency characteristics.

An object of the present invention is to provide a simplified measurement device that takes a short measurement time when measuring detailed frequency characteristics of a high-frequency element.

Hereinafter, FIG. 4 shows a system block diagram of the S-parameter measuring device of the present invention, and the invention will be described in detail.

The upper and lower limits of the oscillation frequency are accurately defined by hardware, and the oscillation signal of the signal generator 11 is synchronized with a signal generator 11 that generates a signal whose oscillation frequency is uniformly changed over time. A network analyzer 14 that detects input and output signals to the device under test 15 and the device under test 1
A measurement system is constructed from a DC bias power supply 16 to 5.

The entire measurable frequency band of the measurement device is divided into bands using the measurement resolution of the network analyzer 14, and the S-parameter of each frequency is measured by sweeping the oscillation signal of the signal generator 11. Only the measured values are output from the network analyzer 14 to an external device.

In this measurement method, it is possible to eliminate the time required to set the measurement frequency and the waiting time for detecting each signal after setting the frequency, and to increase the resolution of the measurement frequency. As long as it is within the set frequency division range, the measurement can be completed in a short time.

The present invention is not only applicable to S-parameter measurements, but can be widely applied to measuring frequency characteristics in other high-frequency characteristics.

[Brief explanation of drawings]

FIG. 1 is a diagram in which a semiconductor element is represented by a two-board blank box. FIG. 2 is a circuit block diagram showing the states of each signal when a semiconductor element is placed on a fixed frequency transmission line. FIG. 3 is a system block diagram of a conventional S-parameter measuring device. FIG. 4 is a system block diagram of an S-parameter measuring device according to an embodiment of the present invention. I,,I,...Human power to semiconductor devices 1st style, v
I+■2... Voltage applied to the semiconductor element, bjl
, +2...Incident voltage to the semiconductor element, Eg, 2
...Reflected voltage from semiconductor element, 1, 11.
... High frequency signal generator, 2 ... Signal shunt, 3 ... Frequency fluctuation detector. 4.14...Network analyzer, 5,
15... Semiconductor element to be measured, 6, 16...
・・Bias power supply for the foot/hand conductor element to be measured, 7・・・・・・
Terminal impedance, 8... impedance,
9... Signal source.

Claims (1)

[Claims] 9, and a network analyzer that detects input and output signals to the device under test.