THE EFFECT OF ALPHA-PARTICLE AND PROTON IRRADIATION ON THE ELECTRICALAND DEFECT PROPERTIES OF N-GAAS

Radiation damage effects were studied in n-GaAs grown by organo-metall ic vapour phase epitaxy (OMVPE) for a wide rang, of alpha-particle (2. 0 MeV and 5.4 MeV) and proton (2.0 MeV) particle fluences, using an am ericium-241 (Am-241) radio-nuclide and a linear Van de Graaff accelera tor as the particle sources. The samples were irradiated at 300 K, aft er fabricating palladium Schottky barrier diodes (SBDs) on the 1.2 x 1 0(16) cm3 Si-doped epitaxial layers. The irradiation-induced defects a re characterized using conventional deep level transient spectroscopy (DLTS). A correlation is made between the change in SBD characteristic s and the quantity and type of defects introduced during irradiation. It is shown that the two parameters most susceptible to this irradiati on are the reverse leakage current of the SBDs and the free carrier de nsity of the epilayer. The introduction rate and the ''signatures'' of the alpha-particle and proton irradiation-induced defects are calcula ted and compared to those of similar defects introduced during electro n irradiation.