ION-IMPLANTATION OF EPITAXIAL GAN FILMS - DAMAGE, DOPING AND ACTIVATION

Monocrystalline GaN films grown on AIN buffer layers previously deposi ted on 6H-SiC(0001) wafers and having dislocation densities on the ord er of 10(7) cm/cm(3) beyond 0.5 mu m from the initial growth interface have been achieved via chemical vapor deposition (CVD), The absence o f low angle grain boundaries invariably extant in GaN films deposited on sapphire substrates and the relatively low dislocation densities an d absence of stacking faults and twinning in the implantation regions of the films make them the best materials available for the study of i mplantation doping, In our initial study, 160 keV Si (n-type) and 120 keV Mg (p-type) with projected range similar to 110 nm and fluences of 1e14, 5e14 and 1e15 cm(-2) were implanted at both room temperature an d 550 degrees C, The samples were characterized by Rutherford backscat tering (RBS)/channeling and photoluminescence (PL) techniques before a nd after implantation, RBS/channeling results of virgin and as-implant ed GaN for 120 keV Mg at 550 degrees C and 1e15 cm(-2) fluence showed that even at this comparatively high dose the implantation damage is v ery little, However the characteristic PL signal which was present bef ore the implantation disappeared even for the lowest dose (1e14 cm(-2) ), These samples were annealed in a rapid thermal annealing furnace at 1000 degrees C, and damage recovery and dopant activation were measur ed by FL, RBS/channeling and Cross-Sectional TEM (XTEM).