(Invited) Schottky Barrier Height Control at Metal/Ge Interface by Insertion of Nitrogen Contained Amorphous Layer

Abstract

Ge is attracted great attention as a candidate of channel material for future CMOS devices and near-infrared optical devices, owing to its high intrinsic carrier mobility and narrow bandgap. One of the difficulties to realize Ge-based devices is to control of Schottky barrier height (SBH) at metal/Ge interface. It is widely known any metal/Ge contact shows high electron barrier height (ΦBN > 0.5 eV) due to Fermi level pinning at metal/Ge interface. Our group found a method to alleviate the FLP, by which sputter-deposited ZrN/Ge contacts showed low ΦBN (< 0.10 eV) and high hole barrier height (ΦBP > 0.56 eV). From detailed structural analyses, FLP alleviation was induced by a nitrogen-contained amorphous interlayer (a-IL) formed during ZrN sputter-deposition. If we can change the kind of metal on a-IL, we may extend the control range of SBH. In this paper, we demonstrate the wide range SBH control for metal/a-IL/Ge contacts.