本論文利用砷化銦材料優異的高電子遷移率及優異電子飽和速度特性，發展次微米電子束微影閘極之低功率高速的異質接面場效電晶體(HFET)。我們也發展了可將汲極與源極的距離縮小的製程。我們觀察到銻化物元件隨著擺放時間的拉長產生了衰化的現象，針對此衰化現象我們也進行了研究。 我們利用改變光阻及控制顯影時間的方式，已可將汲極與源極之距離縮小至1μm。T型閘極長度0.2μm，汲極與源極的距離為1.5μm的元件特性於汲極偏壓VDS=0.4V下，其汲極飽和電流為IDSS=733mA/mm及轉導增益為gm=1,520mS/mm，電流增益截止頻率fT=105GHz。在研究元件衰化現象方面，我們觀察到了和剛製作完成的元件性能相比，元件在經過六個月後的出現了飽和電流增加、轉導增益上升、閘極漏電流變小、以及次臨限電壓位移的現象。我們利用了脈波電流-電壓量測(Pulse-IV)、X光能量色散分析儀(Energy-Dispersive Analysis with X-ray, EDAX)以及小訊號模型來進行分析，發現了元件在經過六個月後，磊晶會和大氣的氧元素發生反應，造成元件的衰化。 We successfully developed low-power and high-speed e-beam submicron gate InAs-channel heterpjunction field-effect transistors in the thesis. A device process flow which includes source-to-drain spacing reduction and e-beam submicron T-gate lithography process was developed. Device degradation mechanism was also studied. The spacing between source and drain can be decreased to 0.6μm by controlling development and baking times. In a HEMT device with a gate length of 0.2μm and a source-to-drain spacing of 1.5μm, IDSS=733mA/mm, gm=1520mS/mm, and the cut-off frequency fT=105GHz at the VDS=0.4V were obtained. Comparing device performance obtained at different times after device fabrication, we found that IDSS and gm increased, IG decreased, and Vth decreased with time. Pulsed I-V, EDAX, and small-signal model analysis suggested that the degradation behavior was very possibly due to the epitaxial oxidation in surface layers.
