Nitridation of an InP(001) surface by nitrogen ion beams

Nitridation of an InP(001) surface with low-energy nitrogen ion beams has b een studied by X-ray photoelectron spectroscopy (XPS) and atomic force micr oscopy (AFM). The efficiency (N Is intensity/total currents) of nitridation decreases monotonously as a function of the beam energy (0.1-3 keV). We fi nd three kinds of chemical states of nitrogen on the irradiated surface. Th e XPS result suggests that they correspond to In-N, In-N-P, and P-N bonding s. The ratio of the In-N bonding for the surface is large at high beam ener gy. Upon annealing the sample irradiated at I keV at RT, the In-N-P bonding disappears and the ratio of the In-N bonding became about 95%. The angle-d ependent XPS In 3d(5/2) spectra suggest that penetrated nitrogen atoms exhi bit the Gaussian distribution in the bulk. The surface irradiated by neutra l nitrogen is flatter than that irradiated by the ions. (C) 2000 Elsevier S cience B.V. All rights reserved.