Lightly n-doped 4H-SiC films, implanted with 1020/cm3 of Al or co-implanted with 1020/cm3 of Al and 1020/cm3 of C, were examined in the unannealed state or annealed at 1300, 1400, 1500, 1600 or 1650C after being coated with an AlN cap. For a given annealing temperature, TA, the sheet resistance, Rsh, was smaller in co-implanted samples at lower TA; but not at higher ones. This was because the C catalyzed chemical reactions for the incorporation of Al into a Si site and, at higher TA, the activation energies for these reactions no longer controlled the reaction kinetics. The cathodoluminescence peak which was created by a free electron recombining with a hole bound to an Al acceptor decreased in intensity as TA was increased. This was because the Al acceptors could be trapped by the deep donors related to a DI defect that increased in number as TA increased. However, the process was thought to be more complicated because the temperature dependence of Rsh implied that the activation energy for conduction was much lower than that of the 0.35eV hole trap. The excellent temperature stability of the DI defect suggested that it was probably associated with defects that nucleated and grew; such as dislocation loops and/or stacking faults. This was consistent with decreased ion-beam channeling at higher TA, and a small anisotropy of the electron paramagnetic resonance peak which was associated with implantation damage. The higher-energy peak in the DI doublet increased in intensity, relative to the lower-energy peak, as TA increased. For a given TA, the relative intensity of the higher-energy peak was larger in the co-implanted samples.

Electrical, CL, EPR and RBS Study of Annealed SiC Implanted with Al or Al and C. K.A.Jones, M.A.Derenge, M.H.Ervin, P.B.Shah, J.A.Freitas, R.D.Vispute, R.P.Sharma, G.J.Gerardi: Physica Status Solidi A: 2004, 201[3], 486-96