Automated system for measuring electrophysical parameters of semiconductor structures

Abstract

сThe article is devoted to the development of an automated information and measurement system for measuring the voltfarad characteristics of semiconductor structures, including structures based on transparent conductive coatings. The structure of the information-measuring system is proposed, the results of functional and metrological analysis of the measurement channel of complex conductivity are presented. In particular, as a result of functional analysis, the functions of converting complex conductivity into a digital code proportional to the capacitive component and the active component of conductivity are obtained. In the process of metrological analysis, a metrological structural model of the complex conductivity measurement channel has been compiled, which, unlike the functional model, takes into account additive, multiplicative errors of the links, as well as the quantization error of the analog-to-digital converter. Expressions are obtained for the real functions of converting complex conductivity into a digital code proportional to the capacitive and active component of conductivity, taking into account the instrumental errors of the links that make up the measuring channel. Metrological analysis makes it possible to solve both the direct problem of calculating the instrumental error of the measuring channel according to the known nominal parameters and errors of its constituent links, and the inverse problem, which consists in assigning requirements to the metrological characteristics of the links in the measuring channels to ensure the required value of the maximum measurement error. In particular, based on the metrological analysis performed, it was found that the limits of the permissible relative error of capacitance and conductivity measurements do not exceed ±3 %, which is confi rmed experimentally. The developed automated information and measurement system allows not only to measure the volt-farad characteristics of the studied semiconductor structures, but also to process measurements in order to determine the electrophysical parameters by an indirect method.