Diamond nucleation enhancement by hydrofluoric acid etching of silicon substrate

We have investigated the effect of silicon substrate pretreatment by hydrofluoric acid (HF) on diamond nucleation. Si (100) substrates were pretreated by ultrasonic scratching with a diamond powder suspension in methanol followed by HF (50%) etching and subsequent water rinsing. The nucleation density (N-D) was found to be up to 30% higher compared to the unetched substrates, provided the rinsing time was short. Such a nucleation enhancement leads to an increased initial deposition rate and to a lower surface roughness of the deposited diamond films. We found that the Si surface termination by H and F atoms after HF etching a thermodynamically favorable configuration to initiate the nucleation process. (C) 1997 Elsevier Science S.A.