Research progress in Ge-based advanced field effect transistor technology

Abstract

The modern integrated circuit is among the world's mostcomplex systems, but at its heart is a very simple, and we think beautiful,device: the transistor. Right now, 7 nm process technology is the cutting edge in traditional silicon-based integrated-circuit-manufacturing industry. However,the downscaling of the technological node in accordance with Moore's Law is becomingincreasingly difficult, not to mention fantastically expensive. Ge has beenconsidered a promising channel material due its high hole andelectron motilities, which facilitate the drive-current boost withoutdownscaling the device's dimensions. This paper summaries the current state-of-the-art Gemetal-oxide-semiconductor field-effect transistors (MOSFETs) from these three angles: gate stacks, source/drainformation, and new device structure. It is found that many criticalphysical and engineering problems concerning Ge MOSFETs are still under discussion, including basic device fabrication and the deep physicalunderstanding of Ge MOSFETs. Nevertheless, Ge MOSFETs reported by bothacademic and industrial researchers show superior performance totraditional Si MOSFETs, suggesting that Ge is a promising material for future high-performance complementary-MOS (CMOS) devices under 3 nm node.