RF Plasma-Enhanced Chemical Vapor Deposition (RF-PECVD) at 13.56 MHz
Posted on August, 08 in COMPUTATION OF SERIES-CONNECTED DEVICE PERFORMANCE
The growth of a-Si and nc-Si by PECVD is a complex process determined by the following factors: plasma properties such as electron density and energy distribution; gas phase reaction chemistry; precursor transport to the growth surface; and surface reactions. Figure 12.10 shows a schematic of a typical RF PECVD chamber and related parts. A silicon-containing gas such as a mixture of SiH4 and H2 flows into a vacuum chamber that is evacuated by a pump. Power from an external RF supply is applied between two electrode plates installed inside; sometimes one is grounded. For a given RF voltage across the plates, there is usually a range of gas pressures for which plasmas occur. The plasma excites and decomposes the gas and generates radicals and ions in the chamber. Substrates may be mounted on one or both of the electrodes, and thin hydrogenated silicon films grow on the substrates as these radicals diffuse into them. The substrates are heated (150-300 °C)