Non-contact method for judging the conductivity type of semiconductor materials

Abstract

The invention discloses a non-contact method for judging the conductivity type of semiconductor material. Existing methods can cause surface damage to the semiconductor material after testing. In the method of the invention, measuring electrodes and reference electrodes are arranged above the surface of the semiconductor wafer to be measured, the electrodes are transparent conductive glass, and the conductive surfaces face downward; the conductive surfaces of the two electrodes are respectively connected to the same-direction and opposite-direction input ends of the operational amplifier; A light source for heating is provided above. First turn off the light source, adjust the output voltage of the operational amplifier to 0, then turn on the light source to heat the partial surface of the wafer, when the operational amplifier has a signal output, turn off the light source; after 3 to 5 seconds, check the output voltage polarity of the operational amplifier: if the polarity is positive , the semiconductor material is P-type; if the polarity is negative, the semiconductor material is N-type. The method of the invention avoids sample damage, is simple in operation, and is easy to realize automation, and simultaneously avoids the semiconductor material entering an intrinsic excitation state due to heating, resulting in judgment failure or erroneous judgment.

Description

technical field [0001] The invention belongs to the technical field of semiconductors and relates to a non-contact method for judging the conductivity type of semiconductor materials. Background technique [0002] The conductivity type of semiconductor materials is one of the important parameters of semiconductor materials. The donor-doped semiconductor material is N-type, and the conduction is dominated by conduction band electrons; the acceptor-doped semiconductor material is P-type, and the conduction is dominated by valence band holes. In research and production, technicians often need to know the conductivity type of semiconductor materials. Commonly used methods to judge the conductivity type of semiconductor materials include thermoelectric potential, rectification, Hall effect, etc. The thermoelectric potential method can be divided into hot probe method and cold probe method. The above-mentioned methods all have a common shortcoming, that is, probes or electrodes...

AI Technical Summary

Problems solved by technology

This method has the following disadvantages: 1) This method is only applicable to SiC materials; 2) For wafers that are polished on the front but sandblasted on the back, it is difficult to measure the transmission spectrum (the absorption spectrum is generally obtained by converting the transmission spectrum, and the wafers that are sandblasted on the back cannot transmit light), so it is difficult to obtain the data of the forbidden band width; 3) the method of determining the forbidden band width from the transmission spectrum is not standardized enough, which can easily cause errors in the measurement of the forbidden band width, so as to draw wrong conclusions. Strictly speaking, it should be in accordance with Tauc The tangent method defined by the equation determines the bandgap width; 4) Due to the complexity of the process from measuring the absorption spectrum and calculating the bandgap width, manual participation is required, and the speed is slow, so it is difficult to realize automated mass screening

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