Annealing treatment of a-Si:H films deposited by PECVD and their properties

The hydrogenated amorphour silicon (a-Si:H) films have been grown on the glass substrates by plasma enhanced chemical vapor deposition (PE-CVD) employing silane (SiH₄) with hydrogen (H₂) dilution. The as - deposited films were then annealed at various temperatures of 200, 300 and 400°C for 30 minutes. Annealing process at 300°C was also performed for 60 and 90 minutes. Examinations using X-ray diffractometry, infrared and UV-Vis spectroscopy demonstrated that the annealed films show an increasing crystalinity of 3.26 - 6.80% and reduced dangling bond content down to more than one order of magnitude (from 2.3 × 10¹⁹ to 1.2 × 10¹⁸ cm^-3). Meanwhile, the energy bandgap and Urbach energy of the films are around 1.71 - 1.75 eV and 0.21 - 0.27 eV respectively.