The Preparation of Transistor Grade Silicon from Silicon or Analogous Compounds

摘要

The preparation, purification and thermal decomposition of silane have been investigated for the purpose of preparing tran¬sistor grade silicon. Yields of 94 to 100$ silane are obtained by the reduction of silicon tetrachloride with various hydrides The reactivity of silane with substances proposed as purifying agents has been studied. Variables in the thermal decomposition of silane have been evaluated with particular emphasis on purity of elemental silicon plus efficiency of dissociation and deposi¬tion rate. Silane has been dissociated on an inductively heated single crystal substrate, producing silicon deposits large enough for single crystal evaluation and neutron activation analysis. A process has been developed whereby silicon can be made con¬tinuously from silane using induction heating.