Negative capacitance effect in semiconductor devices

TL;DR

This paper explores the negative capacitance effect in semiconductor devices, emphasizing the physical mechanisms and interpreting experimental data through transient current analysis, with a focus on quantum well infrared photodetectors.

Contribution

It provides a theoretical and experimental analysis of negative capacitance in QWIPs, highlighting the role of transient injection and recharging effects.

Findings

Negative capacitance observed in QWIPs confirmed experimentally.

Transient current analysis explains the NC phenomenon.

Simulation results support the physical interpretation.

Abstract

Nontrivial capacitance behavior, including a negative capacitance (NC) effect, observed in a variety of semiconductor devices, is discussed emphasizing the physical mechanism and the theoretical interpretation of experimental data. The correct interpretation of NC can be based on the analysis of the time-domain transient current in response to a small voltage step or impulse, involving a self-consistent treatment of all relevant physical effects (carrier transport, injection, recharging etc.). NC appears in the case of the non-monotonic or positive-valued behavior of the time-derivative of the transient current in response to a small voltage step. The time-domain transient current approach is illustrated by simulation results and experimental studies of quantum well infrared photodetectors (QWIPs). The NC effect in QWIPs has been predicted theoretically and confirmed experimentally. The huge NC phenomenon in QWIPs is due to the non-equilibrium transient injection from the emitter caused by the properties of the injection barrier and the inertia of the QW recharging.