Boron and aluminium doping in SiC and its passivation by hydrogen

Extensive calculations regarding the formation energy of interstitial hydro gen and hydrogen-vacancy complexes in different charge states have been car ried out using the local density approximation to ab initio density functio nal theory with a plane-wave basis and norm-conserving pseudopotentials. on supercells of cubic (K) SiC. Based on these results the hydrogen concentra tion of as-grown or H-plasma treated SiC is estimated and its effect on the net carrier concentration is given. Incorporation of B and Al in or withou t the presence of hydrogen has been investigated in hexagonal (4H) SiC supe rcells. The possible origins of the shallow and deep boron acceptors is dis cussed. It is found that the presence of boron promotes hydrogen incorporat ion during growth in the form of passive B + H complexes. The same is not t rue for AL If Al + H complexes are formed (say, after H-plasma treatment), the structure of this complex is different from that of the B + H complexes . The calculated difference between the dissociation energies is 0.9 eV.