SU133117A1 - The method of determining the specific and contact resistance of semiconductor materials - Google Patents

Description

Methods are known for determining the specific and contact resistances of semiconductor materials by connecting a direct current source to the ends of the material and measuring the current in the sample circuit and the voltage drop across the sample and between the probes connected to it.

The predicted method for determining the specific and contact resistances differs from those known in that the voltage measurement is performed by a high-speed self-recording device and, when calculating the resistances sought, only the rapidly increasing ohmic component of the voltage drop is taken into account. The slowly increasing component of the voltage drop is not taken into account, since it is parasitic, because it is caused by the thermoelectromotive force arising in the measuring circuit.

The proposed method allows to increase the accuracy of determining the specific and contact resistances.

FIG. 1 shows a basic electrical circuit for measuring resistances; in fig. 2 shows curves a and b of increasing and decreasing voltage, respectively, on the probes and in the sample.

The ends of the sample / are soldered to two conductors, included in the current (/) and potential (I) circuits. Probes 2 and 5 are fixed on the side surface of the sample. The drop in voltage f / 3 and t /, respectively, on the probes and at the ends of the sample is measured using a high-speed recording potentiometer 4. The current strength is determined by means of the ammeter L, for which current circuit / battery included 5.

No 133117- 2 Total voltage drop on sample /;

(1 IJ1 + IJI.

and the voltage drop across the probes;

f / 3 / p JT ul,

where and is the ohm voltage drop and U is the thermoelectromotive force at the corresponding contacts of the potential circuit.

Elimination of measurement error due to the occurrence of parasitic thermoelectromotive force is based on the slow non-stationary process of establishing the temperature field in the sample due to the Peltier heat and using a high-speed recording device that accurately detects the ohmic voltage drop U between the probes. Denote the current strength by /, the distance between the probes by / i and the sample length by / calculate the resistance R of the sample using the formula:

 -. -J-

To measure the voltage drop on the probes U, the switch 6 is turned to the position "Ub" and the switch 7 closes the current circuit /. On the high-speed potentiometer 4, the voltage rise U curve on the probes is recorded (Fig. 2a).

To determine the contact resistance, the key 6 is set to the position "U" and the key 7 closes the current circuit /. Curve rise; The voltage U on the sample is recorded on potentiometer 4 (Fig. 26). The required contact resistance value is calculated by the formula:

g} ii

p p j

"F- - /,

After the stationary state has been established, / 7 or U opens the key 7 and obtains voltage reduction curves to zero in the same way as its growth curve (Fig. 2a and 26), which can also be used to determine U, t U

Subject invention

The method of determining the specific and contact resistances of semiconductor materials by connecting a direct current source to the ends of the sample material, measuring the current in the sample circuit and the voltage drop across the sample and between the probes connected to it, in order to improve the accuracy of determination The measurement is measured with a fast-acting self-drawing device and, when calculating the sought-for resistances, the ohmic component of the voltage drop is used, regardless of the component of the thermoelectromotive force s.

No. 133117