Remote Plasma Cleaning and Ion-Induced Hydrogen Desorption from the Silicon (100) Surface and Its Applications to Si Epitaxy

ABSTRACTWe have studied the conditions for effective removal of H from the silicon (100) surface by Ar and He plasma bombardment as a function of pressure, plasma power and time. At a given pressure, a range of rf plasma powers exists for effective H-desorption. For example, at 250°C and for 100 mTorr of He, H is desorbed only between 12 and 50W of plasma power. The range of effective powers was found to become narrower with increasing pressure. We have also found the efficacy of the H-plasma clean to be reduced by addition of He and Ar. Substrate damage results from Ar addition and from increased plasma power for pure H. The results are discussed along with Langmuir probe analysis of the various plasma conditions.