OPTIMIZATION OF THE HYDROGEN CONTENT IN A-SI-H DEPOSITED AT HIGH-RATEBY DE MAGNETRON SPUTTERING

Hydrogen content in hydrogenated amorphous silicon deposited at high r ate (around 15 Angstrom/s) by de magnetron sputtering is optimised by varying the hydrogen partial pressure at a given temperature. The effe ct of the hydrogen can be described in two steps: for the hydrogen con tent up to 8 at %, we observe a simultaneous decrease of the deep defe ct density N-D and of the Urbach energy E(O). For the higher contents up to 20 at %, N-D remains nearly constant whereas E(O) increases sign ificantly. Furthermore, we establish that a significant contribution o f polyhydride bonds does not necessary result in poor quality material .