SiGe, GaAs, and InP Heterojunction Bipolar Transistors

CHAPTER ONE

Introduction

Due to the phenomenal growth of applications such as computing and wireless communications, the microelectronics industry, has become a major economic force on the world scene with annual sales in excess of $ 100 billion and continuing growth with no leveling in sight. Competition in this field is fierce among semiconductor companies to maintain their competitiveness and to protect their market share. The explosive demand for low-power wireless communication systems has increased the pace of radio-frequency (RF) technology development. A low-cost, high-performance, highly integrated technology is essential to implementation of wireless communication systems on a chip and makes time to market minimal. The emerging SiGe and InP technologies have the advantage over Si and GaAs technologies of higher-speed performance at low power density.

The concept of the heterojunction bipolar transistor (HBT) was introduced by William Shockley in 1948 (U.S. patent 2,569,347). A detailed theory related to this device was developed by Kroemer in 1957 [1]. The great potential advantages of the heterostructure design over conventional homostructure design have long been recognized [1,2]. It was not until the early 1970s, though, that the technology evolved to build practical transistors of this kind. The situation began to change with the emergence of liquid-phase epitaxy (LPE) as a technology for group III and V compound semiconductor heterostructures. Since the mid-1970s, ...