A new method for the determination of dopant and trap concentration profiles in semiconductors

A new method is described and experimentally verified using a computer-controlled data acquisition system. It is capable of measuring sharply peaked and rapidly varying impurity-concentration profiles in semiconductors, including situations where the trap density exceeds the dopant density, with resolution limited by the Debye length. It combines two well-known techniques: the constant-capacitance junction voltage transient and the quasi-static junction capacitance measurements as a function of dc bias voltage. We propose the acronym CCQS. New implementation methods of these two techniques are developed which offer better reliability, capability, and convenience than those reported previously. The quasi-static low-frequency capacitance is used to obtain experimentally the edge region correction which was estimated only theoretically in the past. The method is verified using gold-diffused p⁺/n and ion-implanted n⁺/p silicon diodes.