Laser‐annealed Si and Se Implants for GaAs microwave devices

We have studied the room temperature annealing of Si‐ and Se‐implanted GaAs, using pulsed Nd:YAG (1.06 μm), pulsed KrF excimer (0.25 μm), and scanned cw Ar (0.488, 0.514 μm) lasers as energy sources. Low‐fluence (1013 cm−2) implants similar to those used for microwave FET channel formation and high‐fluence (3–5×1014 cm−2) implants typical of ohmic contact formation applications were annealed. The primary evaluation technique used has been channeling yield topography (CYT), the Rutherford backscattering equivalent of X‐ray mapping in an SEM. Using our apparus, the lowest channeling yield obtainable is about 0.05 of the random equivalent signal level. Yields below 0.1 of random have been obtained with all three laser. The best result to date has been obtained with the KrF laser, which produced a yield of 0.057 of random.