Heteroepitaxial nucleation of diamond on Si(100) via double bias-assisted hot filament chemical vapor deposition

Abstract

A new process has been developed to obtain high density epitaxial diamond nucleation via a double bias-assisted hot filament chemical vapor deposition (HFCVD). In the process, a negative bias voltage is applied to the Si substrate and a positive bias voltage is applied to a steel grid placed on top of the hot filaments. With this arrangement, a stable plasma can be generated between the grid and the hot filaments. Ions in the plasma are then drawn to the substrate by a negative substrate bias voltage. The impinging rate of these ions can be easily controlled by adjusting the grid current, and the ion energy can be independently controlled by adjusting the substrate bias voltage. Hence, the energy and dosage of ion bombardment onto the Si(100) substrate can be controlled easily and independently. With the controlled ion bombardment, high density and heteroepitaxial nucleation can be achieved routinely. After the nucleation process, highly textured diamond films were grown by either the HFCVD or the microwave plasma chemical vapor deposition process (MPCVD).