Powder Formation in Silane Plasma's. Powder Formation in Silane Plasma's. Philips Solid State Course Plasma Enhanced Chemical Vapour Depositionn Silane Plasmaa Amorphous Siliconn Powder Formationn -transition

This literature survey is performed as a part of the Philips Solid state course It deals with powder formation in silane contain ing plasma s In recent studies substantial progress has been made A detailed powder formation mechanism has evolved which also accounts for the occurence of a so called tran sition Based on the understanding of the particle formation mechanism and the dynamics of particles in a gas ow e ective means to minimise powder formation e ects have been devel oped Conclusions The formation of powder in a silane plasma takes place in three steps In the rst step particles of nm diameter are formed by clustergrowth via ion molecular interactions like SiH SiH Si H H Si H SiH Si H H etc In the next step the particles of nm coagulate to a diameter of nm and in the last step the particles grow to nm Powder forma tion induces a plasma transition from collisional wave riding at the sheath boudaries regime to Joule heating in the plasma bulk referred to here as the regime This transition is associated with powder accumulation in the plasma enhanc ing by a factor of the electron atachment rate Powder formation is e ectively suppressed in modulated plasma s at higher gas temperature c Philips Electronics N V iii