CHARACTERIZATION OF LT GAAS CARRIER LIFETIME IN MULTILAYER GAAS EPITAXIAL WAFERS BY THE TRANSIENT REFLECTIVITY TECHNIQUE

A methodology for determining the carrier lifetime of LT GaAs buffer l ayers in GaAs multilayer wafers utilizing the femtosecond transient re flectivity technique is introduced. Experimental results and computer simulations performed as a function of the LT GaAs growth temperature are presented for the multilayer GaAs structures that are used for dev ice fabrication. The markedly non-exponential nature of the measured t ransients is a consequence of the multilayer structure of the wafers. The carrier lifetime measurements are correlated with available SEU da ta measured for structures fabricated with LT GaAs buffers with differ ent growth temperatures.