Cadmium sulfide surface stabilization and Schottky barrier enhancement for InP based optoelectronic devices

We have investigated the use of CdS interlayers grown by chemical bath deposition (CBD). We have deposited CdS on a wide variety of III-V semiconductors. We found that native oxides were reduced by the CdS treatment. CdS-treated and untreated HEMTs and metal-semiconductor-metal photodetectors (MSMs) were compared. Thin 50 /spl Aring/ layers were effective in reducing gate and surface leakage. The thin CdS layers reduced the gate leakage of InA1As/InGaAs HEMTs and the dark current of InA1As/InGaAs optical detectors. X-ray photoelectron spectroscopy indicates a reduction of surface oxides and the prevention of subsequent group III or V oxide formation. Backside processing of InGaAs/lnA1As MSMs allows complete coverage of the mesas. The CBD process for depositing CdS is inherently adaptable to a wide range of optoelectronic device processes.