High rate growth of microcrystalline silicon at low temperatures

A high rate growth method of microcrystalline silicon at low temperatures has been developed using plasma enhanced chemical vapor deposition (PECVD). It has been found that energetic positive ion and atomic hydrogen impingement on to a growing surface have important affects and that atomic hydrogen density needs to increase correspondingly to the increasing growth rate, while keeping ion bombardment less. Based on this guide line, a novel control of plasma is demonstrated using a high deposition pressure of 2-4 Torr combined with a depletion condition of source gas (SII-L) at a high RF power (a high-pressure-depletion method) and consequently a growth rate of 1.5 nm/s has been achieved using a conventional radio frequency plasma enhanced chemical vapor deposition at 13.56 MHz. Use of a very high frequency plasma at 60 MHz further increases the growth rate up to 5 nm/s and good crystallinity is maintained up to 3.8 nm/s at 250 degrees C. Atomic hydrogen-mediated growth of crystalline silicon at low temperatures is discussed. (C) 2000 Elsevier Science B.V. All rights reserved.