Switching and memory characteristics of ZnSe - Ge heterojunctions

Abstract

Heterojunctions of nZnSe-pGe in which the ZnSe layer is thin and contains a considerable defect density exhibit switching between a high-impedance state of typically 106-107 Ω and low-impedance states three to five orders of magnitude lower, and have the ability to retain either state at zero bias for long periods of time. Switching speeds of 100 nsec or less are observed at repetition rates of 500 KHz, as long as sufficient overdrive is applied to reduce delay times for switching in both directions to negligible values. The effect of temperature on the device parameters is presented, and a model consisting of trap emptying by impact ionization, the formation of current filaments, and the refilling of traps by electron injection is proposed. © 1971 The American Institute of Physics.