Selective chemical vapor deposition of tungsten using WF6 and GeH4

Abstract
Germane (GeH4) has, for the first time, been used as a reducing agent for tungsten hexafluoride in selectively depositing tungsten on silicon. As shown by x‐ray diffraction, films deposited below 400 °C consist of the β‐W phase with A15 cubic crystal structure. This A15 structure proved to be stabilized by germanium which is probably incorporated in the film as a hitherto unknown W3Ge compound. Annealing for 1 h at 575 °C did not change the β‐W structure to the low‐resistivity body‐centered‐cubic α phase of tungsten. The superconducting transition temperature of the films is ≊3 K. The growth rate dependence on temperature, total pressure, and WF6, GeH4, and H2 partial pressure has been investigated. At deposition temperatures above 400 °C the deposited films consist of a mixture of the β and α‐W phase.

This publication has 6 references indexed in Scilit: