Improved hydrogenated amorphous silicon thin films by photon assisted microwave electron cyclotron resonance chemical vapor deposition

The conventional microwave electron cyclotron resonance chemical vapor deposition process has been modified by illuminating the substrate with a tungsten halogen lamp beam of intensity 0.1-1 W/cm² during the deposition of hydrogenated amorphous silicon films. Compared to the conventional process without photon assist, this technique provides improved photoconductivity, carrier lifetime, and solar cell efficiency, as well as reduced light-induced degradation. The efficiency of undoped hydrogenated amorphous silicon/p-type crystalline silicon solar cells fabricated by this process is 10%, without an antireflective coating, and has degraded to only 9.8% after 3 weeks continuous exposure to light.