Selective growth and characterization of doped polycrystalline diamond thin films

Abstract

A process is described to selectively grow B- and P-doped polycrystalline diamond thin films on bare and oxidized silicon substrates by microwave plasma-assisted chemical vapor deposition using a gas mixture of CH 4 and H 2. The resistivity of as-grown B-doped films is decreased by three to four orders of magnitude from the resistivity of undoped films (∼ 10 3 ω cm). The resistivity of undoped films is increased by three to four orders of magnitude when annealed in nitrogen ambient at ∼425 °C for a few hours. The electrical conductivity of B-doped films is measured as a function of temperature. Doped films are analyzed by scanning electron microscopy, Raman spectroscopy, and secondary ion mass spectrometry. Furthermore, attempts have been made to dope diamond with phosphorus, which resulted in an increase in resistivity of the films.