| 摘要 |
PROBLEM TO BE SOLVED: To easily and accurately evaluate emitter-base joint capacity of an important device parameter for determining a high speed property of a bipolar transistor, by performing noise measurement and direct current measurement and performing calculation based on a plurality of specific equations. SOLUTION: Noise characteristic and direct current characteristic of a bipolar transistor are evaluated, and equations I and II between respective parameters of an imaginary number part of the optimal source impedance of noise, direct current gain, and emitter differential resistance, and emitter-base joint capacity are used. Equation I shows, for a frequency of high frequency region less than 1/5 of a cut-off frequency, the imaginary number part XOPT of the optimal source impedance of the bipolar transistor is determined based on only frequency (f) emitter-base joint capacity CBE, direct current gainβ0, and emitter differential resistorγe. Inversely, by measuring the imaginary number part XOPT of the optimal source impedance, the direct current gainβ0, and the emitter differential resistorγe, and using equation II, the emitter-base joint capacity CBE can be evaluated.
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