Chapter 16

Reliability Simulation

M.E. Law, M. Griglione, E. Patrick, N. Rowsey, and D. Horton

Abstract Reliability offers significant modeling challenges. Typically, parts cannot be tested until failure under normal operating conditions. Since the target is frequently a decade or longer of useful life, this is impractical. Consequently, accelerated testing is performed. This procedure only works when the physics is well understood, and the failure mechanism is not accelerated by factors not under the control of the testing. Consequently, modeling of the failure mechanism is crucial in making extrapolated predictions of lifetime. Technology ComputerAided Design tools have advanced to the point where multiple physics can be included and the testing simulated fully. This chapter describes such an extended tool and provides examples of applying it to the understanding of two different failure mechanisms.

16.1Introduction

Reliability offers significant modeling challenges. Typically, parts cannot be tested until failure under normal operating conditions. Since the target is frequently a decade or longer of useful life, this is impractical. Consequently, accelerated testing is performed. For example, testing to failure can be done under higher temperatures and lifetime activation can be extracted. The room temperature operation can then be extracted from the higher temperature and an Arrhenius relationship.

This technique is fine, if the controlling mechanism is simply temperature and the actual channel temperature is well known. GaN/AlGaN HEMT structures are frequently used as power amplifiers, and therefore, the channel temperature can be significantly higher than the ambient. This fact alone would throw off the

M.E. Law (*) • M. Griglione • E. Patrick • N. Rowsey • D. Horton Department of Electrical and Computer Engineering, University of Florida, Gainesville, FL 32611, USA

e-mail: MLaw@eng.ufl.edu

Optical and Electron Devices, DOI 10.1007/978-1-4614-4337-7_16,

# Springer Science+Business Media New York 2013