Selective area growth of InxGa1\u2212xAs nanowires on HfO2 templates for highly scaled nMOS devices

Abstract

The replacement of the strained Si channel in metal-oxide-semiconductor-field-effect-transistors (MOSFETs) with high electron mobility III-V compound semiconductors, particularly InGaAs, is being intensively investigated as an alternative to improve the drive current at low supply voltages in sub-10 nm CMOS applications. As device scaling continues, the reduction of the source and drain contact resistance becomes one of the most difficult challenges to fabricate highly scaled III-V-MOSFETs. In this article, we describe a self-aligned process based on selective molecular beam epitaxial regrowth of InxGa1−xAs (x=0–1) raised source/drain nanowire structures on etched recessed areas of a nanopatterned HfO2 template as a key element to integrate high mobility III-V materials with high-κ dielectrics in three-dimensional device architectures. The interaction of atomic H with the surface of the HfO2 nanopatterns has been investigated by using AFM, ToF-SIMS, and ARXPS. Selective growth has been observed for all values of x between 0 and 1. AFM results show that atomic H lowers the temperature process window for InxGa1−xAs selective growth. HRTEM images have revealed the conformality of the growth and the absence of nanotrench formation near the HfO2 mask edges. InxGa1−xAs alloys grown on H-treated HfO2 patterned substrates exhibit a higher uniformity in chemical composition and full strain relaxation for x≥0.5.