Back to the Future: Germanium nanoengineering reemerges as the savior of Si functional devices

Abstract

Since the inception of the first transistors in 1940s, the immense body of work on the Group IV semiconductors Si and Ge has spearheaded spectacular advances in solid-state electronics development culminating in the modem integrated-circuit (IC) technology that has enabled a vast landscape of device applications in logic, memory, and computing. Although initially Si supplanted Ge as the material of choice for MOSFETs, more recently Ge-based devices are breaking new ground for widespread and innovative applications in electronics, photonics, communications, and sensing devices. Si and Ge, their alloys (SixGe1-x) have numerous applications in CMOS technologies that are applicable for low-cost and high-density ICs, as well as for high-speed electronics and cost-effective photonics through bandgap and strain engineering. We have successfully developed a CMOS-compatible fabrication approach to create new classes of exciting photonic (light emitter and photoMOSFETs) and electronic (single-electron transistors (SETs)) devices. We sincerely believe that our discoveries and developments on the exquisite Ge electronic and photonic devices have only scratched the "tip of the iceberg" in terms of the exciting device possibilities for electronic and photonic integrated circuits (EPICs) on Si platforms.