Electrical activation and carrier compensation in Si and Mg implanted GaN by Scanning Capacitance Microscopy

摘要

We studied the effect of the annealing temperatures (in the 1100-1200°C temperature range) on the electrical activation of ion implanted Si and Mg in GaN Si1" ions were implanted at multiple energies (from 80keV to 180keV) and with a total fluence up to 2 7>=10)4 cm"2 in heteroepitaxial GaN films on sapphire Some samples were subjected to conventional low ramp rate processes at 1100°C and 1200°C in N2 ambient A fast ramp rate pre-annealing in N2 ambient was carried out on other samples before those low-ramp rate processes at 1100°C and 1200°C The calibrated Scanning Capacitance Microscopy (SCM) was applied to determine the active (i e substitutionai) Si depth profile The rapid pre-annealing process leads to an increase from 36% to 63% in the substitutionai Si dose The Mg ions were implanted with energy of 50keV and fluence of 5xlOM cm"2 in n" GaN layer on sapphire Two fast ramp rate annealing process were performed However, only an annealing at 1200°C for 30s in N2 allows to observe, by means of SCM, the formation of a p layer.