Selective area deposition of platinum silicide on exposed silicon areas of n-type, Si(100) substrates patterned with a polyimide resist has been demonstrated by using the thermal decomposition of the molecular precursor, Pt(PF3)(4), under chemical beam conditions. Selectivity was studied as a function of precursor partial pressure, substrate temperature and duration of deposition. Selectivity was most easily obtained at a precursor partial pressure of 1.33 x 10(-4) Pa, substrate temperature of 250 degrees C and deposition times ranging from 18 to 30 min. Atomic force microscopy, Auger electron spectroscopy, and X-ray photoelectron spectroscopy analyses of selectively deposited films strongly suggested the complete interdiffusion of Si and Pt. Speculations on possible mechanisms for selectivity are discussed.