INFLUENCE OF THE TECHNOLOGICAL PARAMETERS ON THE GROWTH OF A-SI-H BY A LOW-PRESSURE DC PLASMA PROCESS

The influence of technological parameters such as the location in the reactor, the pressure and the silane flux on the deposition of hydrogenated amorphous silicon has been studied. The thin films have been grown in a low pressure d.c. hot cathode glow discharge with electrostatic confinement. The electrical parameters of the plasma have been obtained from Langmuir probe measurements. In this type of reactor a high efficiency of silane usage is achieved, which is attributed to the effect of the electrons coming from the hot filament. The changes of the deposition rate with the technological parameters have been studied. The surface structure of the samples is inappreciable in some of them and granular like in others. This structure is favoured by conditions such as the sample orientation in the reactor facing the cathode, high pressures, for which the ion bombardment is lower, and intermediate silane fluxes. The existence of two phases which form a reticular-like structure has been revealed through a strong chemical attack on some samples. SiH is the almost exclusive bond between silicon and hydrogen atoms. © 1990.