Method for measuring semiconductor doping concentration

Abstract

A method for measuring semi-conductor doping density is characterized in that photocarrier radiometric technique and free carrier absorption measurement technique are integrated in a measurement system for simultaneously obtaining the complex radiation signal and absorption signal of the free carrier; the carrier radiation signal and absorption signal of a frequency domain are obtained through varying the modulating frequency of exciting light; the carrier radiation signal and absorption signal of a space domain are obtained through varying the distance between the exciting light and detecting light; and the doping density of the sample to be measured is obtained through comparing with the carrier radiation signal and absorption signal of a standard sample. The invention is based on photocarrier radiometric technique and free carrier absorption measurement technique, and integrates the information of two independent paths in respect frequency domain and space domain, so as to remarkably improve the measurement accuracy of doping density.

Description

technical field [0001] The invention belongs to the technical field of non-destructive testing of semiconductor materials, in particular to a method for determining the doping concentration of semiconductors. Background technique [0002] From the perspective of semiconductor materials, the conductivity of intrinsic semiconductors is very poor. Only when a small amount of impurities are added to change the structure and resistivity, the semiconductor can become a useful functional material. Doping semiconductor materials is the basis of semiconductor devices, and the distribution of doping atoms directly affects the performance of semiconductor devices. Therefore, the precise monitoring and control of the impurity concentration and its uniformity in semiconductors is a very critical technical difficulty in semiconductor manufacturing technology. [0003] The common technologies currently used in the industry for on-line detection of impurity concentrations are the four-prob...

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Problems solved by technology

However, since the reflected signal contains the dual effects of the temperature field and the carrier wave in the semiconductor, it brings difficulties to the measurement calibration and affects the measurement accuracy to a certain extent.

[0004] In 2003, Professor Mandelis of the University of Toronto proposed Photocarrier Radiometry (PCR) technology for the measurement of electron transport characteristics of semiconductor materials and the monitoring of dopant ion concentration and spatial uniformity, because the measurement The signal completely filters out the influence of the temperature field, and the signal decreases monotonously with the increase of the concentration, which greatly improves the signal processing and calibration, but the measurement accuracy does not increase significantly

There are no relevant reports on the integration and application of these two technologies

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