TECHNICAL FIELD

This disclosure relates to techniques for measuring electrical characteristics of a material, and more specifically, techniques for measuring electrical characteristics of semiconductor materials using a non-destructive multi-point probe.

BACKGROUND

The purpose of using four-point or 4-point probes (“4PPs”) is to measure a resistivity of a material, such as a semiconductor material. For example, 4PPs are used to measure an electrical impedance using separate pairs of current-carrying and voltage-sensing electrodes. In some instances, a 4PP may include four equally spaced probes having metal tips with a finite but very small radius (i.e., the “points” of the probe). During measurements, a high impedance current source is used to supply current through the outer two probes, and a voltmeter measures the voltage that is produced across the inner two probes to determine the sample resistivity. However, standard or conventional 4PPs techniques are generally destructive because they are manufactured using sharp metals, and moreover, standard 4PPs cannot provide accurate measurement if probe/semiconductor contact resistance is too high. Additionally, standard 4PPs techniques are limited to resistivity measurements and cannot be used to gain insight into other characteristics of the semiconductor material.

SUMMARY OF THE DISCLOSURE

The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

In an aspect, the present disclosure is directed to an elastic multi-contact probe. The elastic multi-contact probe may include multiple conductive strips each of which comprises a conductive elastomer. The conductive strips may be spaced apart from each other and a front surface of the conductive strips is configured to be placed on a surface of a substrate to be probed. The elastic multi-contact probe may also include multiple dielectric strips. Each of the dielectric strips may be formed on a back surface of a respective one of the conductive strips. The elastic multi-contact probe may further include a single layer of a thermoplastic formed on back surfaces of the dielectric strips such that the dielectric strips separate the conductive strips from the single layer of the thermoplastic.

In another aspect, the present disclosure is directed to a method for performing a measurement of a surface area of a semiconductor material. The method may include measuring a first current-voltage (I-V) curve between a pair of inner probes of multiple probes of an elastic multi-contact probe based on a first current applied to a pair of outer probes of the probes. The method may also include determining a first slope of a linear region of the first I-V curve. The method may further include measuring a second I-V curve between the pair of inner probes based on a second current applied to the pair of inner probes. The method may also include determining a second slope of a linear region of the second I-V curve. The method may also include calculating a sheet resistance and a contact resistivity of the semiconductor material based on the first slope and the second slope.

In another aspect, the elastic multi-contact probe, or variations thereof, may be used to perform measurements on the surface area of a semiconductor material to obtain or calculate a sheet resistance, a contact resistivity, or both, of the semiconductor material.

