Abstract:
Germanium is successively epitaxially deposited on and etched from a substrate 11 of Ge, GaAs, GaP or InSb by reacting HI in a H2 and He gas stream with a heated Ge bed 9 and passing this stream over the substrate at a lower temperature than the bed 9. Pulsed UV light from a Xenon source 12 irradiates the substrate Ge being deposited when the light is off and removed when the light is on, the pulse frequency may vary during the process. HI is formed by passing a mixed controlled flow of H2 and He through a heated iodine crystal bed 4 and then through a platinum wool catalyst chamber 8. In one example a single crystal substrate is continuously irradiated and the surface etched by the gas stream.ALSO: In a method of depositing Ge (see Division C7) HI is formed by passing a mixed controlled flow of H2 and He through an iodine crystal bed 4 in a thermostatically controlled oil bath at 50 DEG C. and then through a platinum wool catalyst chamber 8 at 300-400 DEG C. Sufficient hydrogen is provided to ensure complete conversion of iodine from the bed 4.