Ohmic Contact Formation of Sputtered TaN on n-Type Ge with Lower Specific Contact Resistivity

Abstract

Modulation of the effective Schottky barrier height of Al/TaN/n-Ge Schottky junctions by varying TaN thickness and ohmic contact formation on n-type Ge substrates is reported. A specific contact resistivity of 2.7×10−5 Ω·cm2 is achieved for a Al/TaN(400/15 nm) layer on moderately doped n-type Ge, which is smaller by two orders of magnitude compared with that of an Al layer (1.2×10−3 Ω·cm2) in direct contact with the same wafer. Sputtering a thin TaN layer on n-Ge effectively improves the contact resistivity of a metal/n-Ge contact by significantly reducing the effective Schottky barrier height, facilitating the fabrication of high-performance Ge devices.