The Study On PECVD Key Technologies Of Amorphous Silicon Thin Film Solar Cell

Plasma-Enhanced Chemical Vapor Deposition (PECVD) is the most widely used technology to preparation of a-Si: H amorphous thin-film solar cell's thin film. Because of high visible light absorption coefficient, Raw material origin is widespread, and large area thin film deposition with low cost enables the amorphous thin-film solar cell to have the broad application prospect. Then it requires high technical performance to PECVD depositing the high grade amorphous silicon membranous material. And the key technologies in system's reaction chamber include electric field, temperature field, flow field and the auxiliary magnetic field distribution.This paper used the computer numerical simulation method to analysis the items to the PECVD key technologies. First, establish plate electrode model, Study the influence of power frequency, feeding point and electrode size. Then whole heating and substrateholder heating styles two kind of temperature fields were Simulation calculation, as well as"electrode spraying"and"cross-ventilation"two kinds of inlet gas distribution mode.The results show that the higher frequency, the larger electrode area obtained the more obvious non-uniformity of the electric field.The substrate surface temperature is uniform with whole heating style, while substrate edge temperature declines with substrateholder heating style.There is high gas pressure in the central part of electrodes and low pressure in the edge part by"electrode spraying"style. And there is low gas flowrate in the central part of electrodes and low flowrate in the edge part. With the increase of gas flow into, the substrate surface pressure distribution and flow velocity uniformity increase linearly. The pressure reduces gradually from the air inlet to the air outlet by"cross-ventilation"style gas inlet, the gas flow is wholly uniform.Solenoid magnetic field and magnetic-mirror field were analysed, the existing magnetic field was improved by designing a solenoid magnetic field. Analysis both the radial and axial magnetic mirror confined plasma produced by the magnetic field, as well as the magnetic mirror ratio adjusting method. The distributions of two kinds of magnetic fields were obtained.Through the research of field distribution characteristics, the PECVD main design was proposed: whole heating style, 13.56MHz RF power, With no side shields of plate spray intake,"electrode spraying"gas inlet style, electrode plate spacing is about 40mm, good performance parameters can be achieved.This study provides a theoretical basis on the preparation of a-Si: H thin films of PECVD technology.