Flux and fluence dependence of implantation disorder in GaAs substrates

A previously presented technique of measuring radiation damage using electroreflectance (ER) measurement is used to detect disorder dependencies for light and heavy ions as a function of flux and fluence. Lighter-mass ions (Ne, N, and O) cause increasing damage with increasing flux for fluences less than 5 x 1013 cm-2 because of the decrease in radiation-enhanced annealing. At higher fluences, the damage decreases with increasing flux probably because of thermal annealing. Heavy ions (Cd, Te, and Xe) exhibit the same type of behavior but at lower fluences because of the smaller penetration depths. The ER measurements of damage in ion-implanted GaAs show clearly that the radiation-enhanced and thermal-annealing processes depend upon the energy density and damage concentration in the crystal