Low-temperature growth of GaAs on Si used for ultrafast photoconductive switches |
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Authors: | Kai Ma Urata R Miller DAB Harria JS Jr |
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Affiliation: | Solid State & Photonics Lab., Stanford Univ., CA, USA; |
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Abstract: | GaAs was grown directly on silicon by molecular beam epitaxy (MBE) at low substrate temperature (/spl sim/250/spl deg/C). Both the silicon wafer cleaning and the GaAs film growth processes were done at temperatures lower than the Si-Al eutectic temperature to enable monolithic integration of low-temperature-GaAs photoconductive switches with finished Si-CMOS circuits. The film surfaces show less than 1 nm rms roughness and the anti-phase domain density is below the detection limit of X-ray diffraction. Metal-semiconductor-metal photoconductive switches were made using this material and were characterized using a time-resolved electrooptic sampling technique. A full-width at half-maximum switching time of /spl sim/2 ps was achieved and the responsivity of switches made from low-temperature GaAs on Si material was comparable to its counterpart on a GaAs substrate. |
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