Influence of boron concentration on the XPS spectra of the (100) surface of homoepitaxial boron-doped diamond films

As-grown (100) homoepitaxial diamond films with boron concentrations [B] from 4.6 x 10(16) to 1.5 x 10(21) cm(-3) have been analysed using X-ray photoelectron spectroscopy (XPS). Their C is core levels contain a dominant component around 284.17 +/- 0.2 eV ascribed to sp(3) C and a main secondary component around 284.88 +/- 0.2 eV ascribed to CHx (x >= 2) on surface defects. Their relative concentration decreases and increases, respectively, as [B] increases. A significant component around 286.4 +/- 0.2 eV ascribed to ether group (C-O-C) remains nearly constant up to [B] approximate to 3 x 10(20) cm(-3), then increases for greater boron concentrations. Other components around 283.0 +/- 0.2, 287.69 +/- 0.2 and 288.76 +/- 0.2 eV ascribed, respectively, to sp(2) C, carbonyl (C=O) and carboxyl (HO-C=O) on surface defects remain with low concentrations. The occurrence of these XPS components, their assignments and their relative concentrations are satisfactorily compared to those previously found for IIb crystals with (100) surface and for polycrystalline films with [B] around 10(19) and 7 x 10(20) cm(-3). (c) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.