Direct fusion bonding of silicon to polycrystalline diamond

High temperature fusion of silicon to diamond is reported. Polished, randomly oriented diamond films and unpolished (100) highly oriented diamond films were bonded to single-side polished (100) silicon in a dedicated ultrahigh vacuum bonding apparatus. Direct bonding under an applied uniaxial stress of similar to32 MPa was observed at temperatures above 950 degreesC. The bonded interface was examined by scanning acoustic microscopy revealing only partial bonding at fusion temperatures of 950 and 1050 degreesC. In contrast, complete bonding was evidenced at 1150 and 1200 degreesC, although cracking of the diamond films became more prominent at these higher fusion temperatures. (C) 2002 Elsevier Science B.V. All rights reserved.