Influence of the pretreatment anneal on Co germanide Schottky contacts

TL;DR

This study examines how different annealing pretreatments affect the formation and properties of Co germanide Schottky contacts, revealing significant impacts on barrier characteristics and interdiffusion behavior.

Contribution

It provides new insights into how high-temperature pretreatments influence germanide formation and Schottky barrier properties in Co/Ge contacts.

Findings

700°C pretreatment removes native oxide but increases contaminant diffusion

700°C pretreatment leads to double layer structure after annealing

400°C pretreatment results in isolated germanide islands

Abstract

A thin cobalt layer is deposited by electron beam evaporation onto a germanium substrate after an in situ cleaning annealing at 400 or 700 C. The effect of these pretreatments on the Co/Ge Schottky barrier properties and on the germanide formation is investigated by using different techniques. A strong influence of the pre-treatment is observed. The pre-treatment at 700 C removes the native oxide but enhances the diffusion of contaminants. After post-metal deposition annealing, the sample pre-treated at 700 C shows a double layer structure due to interdiffusion, whereas some large isolated islands are present in the sample pre-treated at 400 C.