DEFECT FORMATION AND ANNEALING BEHAVIOR OF INP IMPLANTED BY LOW-ENERGY N-15 IONS

Defect formation has been studied in nitrogen-implanted III-V compound semiconductor material InP. Sulphur-doped n-type (100) InP samples we re implanted at room temperature with 30 keV N-15(+) ion doses of 10(1 4)-10(16) N atoms cm(-2). The implanted samples were subjected to isoc hronal vacuum annealing in the temperature range of 450-650 degrees C. The annealing behavior of nitrogen atom distributions, implantation-i nduced displacements of indium atoms, vacancy-type defects, and damage annealing were studied by nuclear resonance broadening, secondary ion mass spectrometry, ion backscattering and channeling, and slow positr on annihilation techniques. Doses above 10(15) N atoms cm(-2) were fou nd to, produce amorphous layers extending from the surface to depths b eyond the deposited energy distribution, up to 110 nm. The depth of an amorphous layer was observed to depend on the implantation dose. Temp erature and dose-dependent epitaxial regrowth starting from the amorph ous-crystalline interface was observed at 575 degrees C. The damage an d vacancy concentration distributions were correlated with the implant ed nitrogen distribution in the case of the highest implantation dose at 10(16) N atoms cm(-2); disorder annealing and loss of nitrogen beha ve in a like manner with increasing temperature. For the lower doses, however, almost no redistribution or loss of nitrogen arose despite st ructural damage and vacancy annealing. Interpretation of the positron data allowed an identification of two types of vacancies. The type of the vacancy defects was found to depend on the implantation dose and a nnealing temperature; monovacancies were formed in the In sublattice a t the low implantation doses, while the highest dose produced divacanc ies. The annealing tended to convert the monovacancies into divacancie s, which were recovered at high temperatures depending on the implanta tion dose. (C) 1998 American Institute of Physics. [S0021-8979(98)0740 2-7].