ADSORPTION OF SIH4 OR SI2H6 ON P SI(100) AT ROOM TEMPERATURES/

Effects of predeposition of phosphorus on room temperature adsorption of SiH4 or Si2H6 on Si(100) surfaces have been investigated by H-2-tem perature-programmed-desorption measurements. As a result, it was clari fied that the amount of adsorbed SiH4, or Si2H6 molecules after satura tion, as measured from the hydrogen coverage theta(H)(sat), decreases from that on a bare-Si surface, satisfying the relation theta(H)(sat) + theta(P) = 1, with theta(P) the predeposited phosphorus coverage. Th is relation indicates that neither SiH4 nor Si2H6 chemisorbs at phosph orus sites at room temperatures. For initial adsorptions, by contrast, the adsorption of SiH4 or Si2H6 were less affected, for which migrati on of physisorbed molecules from P-sites toward bare-Si sites is sugge sted. (C) 1998 Elsevier Science B.V. All rights reserved.