CHARACTERIZATION OF INDIUM-PHOSPHIDE AND GALLIUM-ARSENIDE BY THE SURFACE PHOTOVOLTAGE TECHNIQUE (SEMICONDUCTORS, RADIATION DAMAGE, DIFFUSION LENGTH).

摘要

A general theory for the surface photovoltage (SPV) technique is developed. Goodman's original SPV theory is shown to be a limiting case.; The effect of the additional light produced by the radiative recombination process of electron-hole pairs in semiconductors is examined. Numerical simulation shows that it merely results in a higher effective minority carrier diffusion length, while the SPV technique remains simple to interpret.; The SPV technique is then used to determine the electron diffusion length and the optical absorption tail of a series of manganese (Mn) doped p-type indium phosphide (InP) single crystal samples. Both the electron diffusion length and the optical absorption tail are found to depend strongly on the hole concentration as well as the defect density of the crystals. Using a liquid electrolyte in contact with the semiconductor to set up the surface barrier and thus to collect the SPV signal, we demonstrate that this technique is particularly convenient and easy to apply.; A new depth profiling technique is developed to study the radiation damage in gallium arsenide (GaAs) and InP single crystals induced by the low energy ((TURN) 500 eV), high dose ((TURN) 3 x 10('18 )cm('-2)) argon ion (Ar('+)) beam milling process. This technique combines successive anodization (for removing the damaged semiconductor layer) with in situ SPV measurements (for monitoring the damage). Deep level defects in the damaged region are found within (TURN) 250 (ANGSTROM) from the milled surface.