Semiconductor Measurement Technology: A 25-kV Bias-Isolation Unit for 1-MHz Capacitance and Conductance Measurements.

摘要

The report describes a technique for using a commercially available C/G-meter with a Bias-Isolation Unit (BIU) for C and G measurements at bias-voltage magnitudes up to 25kV without damage to the measurement equipment. The basic principles of operation and the details of the electrical design of a BIU are presented. The use of the BIU imposes certain limitations on the range of sample capacitance and conductance that may be measured without introducting excessive error. The theory of these limitations is presented and compared with experimental results obtained from the use of the BIU. The measurement capability demonstrated by these results is adequate for the intended silicon-on-sapphire measurement application and may be described in terms of a measurement range for a maximum added error due to the use of the BIU. For less than plus or minus 1% added error in the indicated (measured) capacitance,the measurable range of the sample capacitance is found to be from 0to about 100 pF. In this application,it is also important to be able to accurately measure small changes in the sample capacitance;for less than plus or minus 1% added error in the indicated (measured) value of a small change in the sample capacitance,the measurable range of the sample capacitance is found to be from 0to about 38 pF. Conductance measurements may be made with less than about 2% added error for samples whose capacitance is in the range 0to 50 pF.