PURPOSE: To relieve attack of cations during formation of amorphous thin films and to decrease damages to the thin films, by holding a glow discharge power at or near a minimum level capable of causing the glow discharge for a predetermined period from the start of the discharge.
CONSTITUTION: Substrates 1 are disposed on a support 16 in a reaction chamber 11. Silane gas is introduced into the reaction chamber 11 while the reaction chamber is evacuated. While the substrates 1 are heated by a heater 17, a high-frequency voltage is applied between electrodes 12 and 13 by a high-frequency power supply 14 so as to create glow discharge plasma. If the minimum power capable of causing the glow discharge is held for 30 seconds or more from the start of the discharge, I-type layers can be prevented from being damaged by attack of cations. If the minimum power is held for more than three minutes from the start of the discharge, however, it cannot be expected to improve the performance any more. In view of productivity and deterioration of elements due to thermal diffusion of impurites, it is advisable to increase the power before three minutes elapses from the start of the discharge so as to increase the film forming speed.
OKAMOTO HIROAKI
MORITA SHOJI
MITSUBISHI HEAVY IND LTD
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