p-type doping in a-Si1-xCx : H obtained by PECVD

In previous works we have pointed out the importance of the so-called 'sila ne starving plasma' condition on the optical, chemical and structural prope rties of a-Si1-xCx:H obtained by standard radio frequency plasma enhanced c hemical vapor deposition (PECVD) technique from silane (SiH4) and methane ( CH4) gaseous mixtures. We have shown that the n-type doping efficiency obta ined by ion implantation of phosphorous and nitrogen in samples grown in th e 'starving plasma' condition improves the n-type conductivity up to levels close to those obtained in device quality a-Si:H. In this work we study th e p-type doping of these PECVD films by adding aluminum and boron, as accep tor impurities, to close to stoichiometry a-SiC:H films grown in 'starving plasma condition' with and without H-2 dilution. Boron was introduced by io n implantation and aluminum by low temperature thermal diffusion. The resul ts indicate that, even though the attained conductivity levels are not devi ce levels, the aluminum doping is more efficient than boron, in accordance to observation of crystalline SIC material. (C) 2000 Elsevier Science B.V. All rights reserved.