Influence of deep traps on the measurement of free-carrier distributions in semiconductors by junction capacitance techniques

Abstract

A generalized model is developed for the electronic behavior of deep traps in a p‐n‐junction depletion region. The depletion region is shown to consist of two parts: (i) a space‐charge region which is totally depleted of free carriers and (ii) a transition region which is only partially depleted. The influence of this junction structure on free‐carrier profiling measurements is considered in detail for donor and acceptor traps with both homogeneous and inhomogeneous spatial distributions. Experimental observations of deep‐trap distributions produced by proton bombardment of n‐type silicon are analyzed within the framework of the model. Implications of the model in the measurement of junctioncapacitance transients and photocapacitance are considered in Appendices A‐C.