EFFECT OF SUBSTRATE PRETREATMENT ON DIAMOND DEPOSITION

A p-type (100) Si wafer is pretreated with diamond, c-BN, MoB, LaB6 TaB2 or Si powder suspended in acetone by an ultrasonic method and the deposition of diamond at an early stage in a microwave plasma is observed with a field emission scanning electron microscope. In all cases diamond is deposited preferentially on the surface of abrasive residues. The deposition rate of diamond from the vapour phase within 1 h is in the order Si < TaB2 < c-BN, MoB, LaB6 < diamond, showing that c-BN, MoB and LaB6 are equally effective for diamond formation. However, the role of implanted particles is different for each species. Textured diamond particles are formed on the surface of c-BN single crystals. LaB, single crystals, in contrast, are strongly etched by the plasma and only polycrystalline diamond particles are formed. The enhancement with Si particles seems to be due to the formation of carbide film.