Film deposition of amorphous films with a graded bandgap by electron cyclotron resonance

Abstract

A method is described of forming a film of an amorphous material on a substrate (14) by deposition from a plasma. The substrate (14) is placed in an enclosure, a film precursor gas is introduced into the enclosure through pipes (20), and unreacted and dissociated gas is extracted from the enclosure through pipes (22) so as to provide a low pressure therein. Microwave energy—is introduced into the gas within the enclosure as a sequence of pulses at a given frequency and power level to produce a plasma therein by distributed electron cyclotron resonance (DECR) and cause material to be deposited from the plasma on the substrate. The frequency and/or power level of the pulses is altered during the course of deposition of material, so as to cause the bandgap to vary over the thickness of the deposited material.

Dependencies are inferred from the claim text.