CHARACTERIZATION OF UNDOPED AND DOPED HOMOEPITAXIAL DIAMOND LAYERS PRODUCED BY MICROWAVE PLASMA CVD

Undoped and doped homoepitaxial diamond films were grown selectively o n synthetic diamond substrates by microwave plasma chemical vapor depo sition. Doping was carried out using B2O3 powder. The films were chara cterized using a Talystep profilometer, reflection high energy electro n diffraction, Nomarski microscopy and scanning laser microscopy. The electrical properties were specified by current-voltage and Hall effec t measurements. The electric conductivity of the substrates and of the homoepitaxial layers was measured at temperatures up to 400-degrees-C . The morphology of the undoped films changes from scaly growth at low methane concentrations to layer growth at higher concentrations. The conductivity of the undoped films is lower than the conductivity of th e substrate. The electric conductivity of boron-doped films shows an a ctivation energy depending on boron concentration.