SELECTIVE GROWTH AND CHARACTERIZATION OF DOPED POLYCRYSTALLINE DIAMOND THIN-FILMS

A process is described to selectively grow B- and P-doped polycrystall ine diamond thin films on bare and oxidized silicon substrates by micr owave plasma-assisted chemical vapor deposition using a gas mixture of CH4 and H-2. The resistivity of as-grown B-doped films is decreased b y three to four orders of magnitude from the resistivity of undoped fi lms (almost-equal-to 10(3) OMEGA cm). The resistivity of undoped films is increased by three to four orders of magnitude when annealed in ni trogen ambient at approximately 425-degrees-C for a few hours. The ele ctrical conductivity of B-doped films is measured as a function of tem perature. Doped films are analyzed by scanning electron microscopy, Ra man spectroscopy, and secondary ion mass spectrometry. Furthermore, at tempts have been made to dope diamond with phosphorus, which resulted in an increase in resistivity of the films.