ELECTRICAL AND OPTICAL CHARACTERIZATION OF CD-IMPLANTED GAAS( AND P+ DUALLY ION)

Electrical and optical properties in Cd+ singly and Cd+P+ dually impla nted GaAs have been investigated. Samples were annealed by a furnace a nd characterized by the Van der Pauw method at room temperature and ph otoluminescence (PL) measurement at 2 K. It is found that a higher act ivation efficiency of the Cd impurities could be obtained by coimplant ation of phosphorous ions. The optimum condition is that Cd+ ions and P+ ions are implanted with the same concentration for high dose implan tation. In PL spectra, the intensity of the conduction band to Cd acce ptor transition, (e,Cd), in the Cd+ implanted sample increases with in creasing phosphorous concentration, which is consistent with the elect rical results. PL spectra at the long wavelength region measured by a germanium detector show that P+ ion coimplantation does not produce an y deep levels in GaAs. All the results indicate that phosphorous is an ideal species for coimplantation.