Germanium nanowire metal-oxide-semiconductor field-effect transistor fabricated by complementary-metal-oxide-semiconductor-compatible process

Abstract

This work presents a complementary metaloxidesemiconductor-compatible topdown fabrication of Ge nanowires along with their integration into pMOSFETs with "HfO2/TaN" high-k/metal gate stacks. Lateral Ge wires down to 14 nm in diameter are achieved using a two-step dry etch process on a high-quality epitaxial Ge layer. To improve the interface quality between the Ge nanowire and the HfO2, thermally grown GeO2 and epitaxial-Si shells are used as interlayers. Devices with a GeO2 shell demonstrated excellent ION/I OFF} ratios (>106), whereas the epitaxial-Si shell was found to improve the field-effect mobility of the holes in Ge nanowires to 254 cm2V -1.s-1. © 2010 IEEE.