CLOSED-CHAMBER CHEMICAL-VAPOR-DEPOSITION - NEW CYCLIC METHOD FOR PREPARATION OF MICROCRYSTALLINE SILICON FILMS

A new cyclic chemical vapor deposition (CVD) process for low-temperature preparation of microcrystalline silicon and its alloys is proposed. The cycle includes an a-Si:H layer deposition step and a hydrogen-radical treatment step. The H-treatment step is carried out under closed-chamber CVD (CC-CVD). It provides conservation of Si mass at an equilibrium between H-etching and redeposition. Thus, films of high crystallinity can be achieved. The advantages are a high deposition rate, high reactive gas utilization and precise control of the film structure. In situ monitoring of the plasma emission spectrum has been used to investigate the CC-CVD process features. The films are characterized by Raman spectroscopy, scanning electron microscopy, temperature-dependent dark conductivity, and infrared transmission spectroscopy.