Ni(Ge1-xSnx) ohmic contact formation on N-Type Ge1-xSnx using selenium or sulfur implant and segregation

Abstract

The physics of ohmic contact formation for nickel stanogermanide [NiGe 1-xSnx)] on n-type germanium-tin (n-Ge 1-xSnx) was investigated. Low-resistivity Ni(Ge 1-xSnx) was formed on Ge1-xSnx using a 350 °C30-s anneal. Ion implantation of selenium (Se) or sulfur (S) into n-Ge1-xSnx followed by nickel stanogermanidation led to the segregation of Se or S at the Ni(Ge1-xSnx)n-Ge 1-xSnx interface. Low effective electron Schottky barrier height (ΦB n) of 0.12 and 0.11 eV was achieved for Ni(\hboxGe1-xSnx)n-Ge1-x Snx contacts with Se and S segregation, respectively. A simulation study was also performed to explain the experimental observations. Se and S atoms could be modeled as donor-like traps near the Ni(\hboxGe1-xSn x)n-Ge1-xSnx interface, modifying the potential profile near the contact and giving rise to trap-assisted tunneling to increase the reverse leakage current for ohmic contact formation. © 1963-2012 IEEE.