Noise in SiGe HBTs: opportunities and challenges (Keynote Address)

Abstract

SiGe technology represents a remarkable success story for the microelectronics industry, and possesses the capability to fundamentally reshape the way broadband communications systems are conceived and built in the 21st century. From the first demonstration of a functional SiGe HBT in 1987, until the achievement of the present performance record of 375 GHz peak cutoff frequency, a mere 18 years has elapsed! The SiGe HBT is the first practical bandgap-engineered Si device, and has evolved from simple transistor and circuit demonstrations in a select few research laboratories to robust production in upwards of two-dozen manufacturing facilities around the world in 2005, and commercial products abound across a wide spectrum of commercial applications. This paper reviews the state-of-the-art in SiGe technology, discusses the design and operational principles of SiGe HBTs, and then focuses on the broadband and low-frequency noise characteristics of SiGe HBTs, emphasizing both the opportunities and the challenges which will necessarily be faced with continued device scaling.