P-type Doping of Epitaxial 3C-SiC Layers on Silicon (001)

Single-crystalline 3C-SiC epitaxial layers were grown on on-axis Si (001) substrates by low-pressure hot-wall chemical vapour deposition. Aluminium front a trimethylaluminium (TMA) source was used for p-type doping. The atomic Al and carrier concentrations in the layers were determined as a function of the partial pressure of the TMA Source gas. Secondary ion mass spectroscopy (SIMS), Hall-effect measurements at room temperature and four-point electrical resistivity method were applied to measure the atomic and electrically active Al concentrations. The crystalline perfection of the layers was characterized by high-resolution x-ray diffraction (HRXRD). At TMA-partial pressures ranging from 5 x 10(-7) mbar tip to 1.5 x 10(-4) mbar corresponding aluminium concentrations from 2 x 10(15) cm(-3) to 1.3 x 10(19) cm(-3) were measured in the epitaxial layers. On increasing the Al concentration from 1 x 10(17) cm(-3) to 1 x 10(19) cm(-3) the layer electrical resistivity decreases from 17 Omega cm to 0.8 Omega cm. while no influence oil the crystalline quality of the layers was observed. The average full width at half maximum (FWHM) of the rocking curve for a 5 mu m thick 3C-SiC layer is about 500 arcsec. With increasing layer thickness (tip to 16 pin) the FWHM of the rocking Curve decreases to about 300 arcsec.