STRUCTURAL-CHANGES OF A-SI-H FILMS ON CRYSTALLINE SILICON SUBSTRATES DURING DEPOSITION

In situ measurements of the transient photoconductivity during the deposition of amorphous silicon films on single-crystalline silicon substrates indicate a drastic increase of the surface recombination at the interface immediately after the start of the plasma discharge. This can be attributed to an initial damage of the substrate surface by impact of plasma-induced species on the silicon surface. The subsequent deposition of amorphous silicon films leads to a quenching of this plasma-induced surface recombination where this quenching process is faster at higher deposition temperatures. This passivation process is attributed to an interfacial relaxation occurring under influence of plasma-induced species even at an appreciable thickness of the a-Si:H film deposited. It is proposed that this process is an aspect of a general structure relaxation process in the material.