本論文使用PECVD疊層技術，利用氫原子電漿處理技術打斷通入SiH4及GeH4的Si、Ge之鍵結，進而結合成奈米複晶矽鍺薄膜。並利用FESEM、AFM觀察薄膜的表面狀態，使用Raman spectra、FTIR等儀器分析薄膜的結晶品質，以及使用PL來量測其吸收光譜。
本文主要的內容在研製在玻璃基板上以nc-SiGe為材料所成長的能障型光電晶體，並探討其照光及不照光之電性。此元件因基極層的P型薄膜非常薄，在不照光時，任何偏壓下P層內都無自由載子。且電流能藉由外加偏壓改變的能障來控制，以加速元件的交換速率。又在照光下，因光激電洞在能障區堆積，使得能障高度下降，導致大量的電子由射極放射至集極，而產生大的光電流。
此外，我們討論了元件在未照光與照光下的I-V特性、光增益、光譜響應及響應速度等。在VCE等於5V時以波長700nm，5mW之雷射光照射下可得到的最大光增益為25；響應速度的上升時間可達10μs，下降時間則為10μs。這些結果比起非晶矽能障型光電晶體的光增益為3.2；響應速度的升降時間為30μs[27]，本元件更適合作為高增益且高速的紅外線光感測器之用。

In this thesis, we used layer-by-layer method (LBL), to develop nc-SiGe phototransistor on glass substrate. The LBL method takes the advantage of hydrogen plasma annealing to break the bonds within Si and Ge compound, thus growing the nc-SiGe thin films effectively. Firstly, we investigated physical, optical and electrical characteristics of the films by FE-SEM, AFM, Raman spectrum, Photoluminescence, respectively to optimize the depositing parameters. Then the optimized parameters were employed to prepare nc-SiGe bulk barrier phototransistors on glass substrate.
The device has an ultra thin base layer, so that the current flow is controlled by the potential barrier of the device. Through an external voltage, one can control the barrier height to speed the operation of device. In addition, under illumination, the photo generated holes are accumulated in the potential valley (at the base region), thus lowering the barrier height, and resulting a lot of electrons inject from emitter to collector, and in turn a large photo current.
Furthermore, we investigated the I-V characteristics of the device with and without the illumination of an infrared light source. Optical gain, spectrum response, and response speed were be measured. At 5V VCE bias, and under 5mW at λ=700nm laser diode illuminated, the maximum optical gain is 25; the response speed for rise time is 10μs, and 10μs for fall time. These data are better than 3.2 for optical gain, and 30μs for response time of the amorphous Silicon bulk barrier phototransistors, thus the developed. Thus, the developed nc-SiGe bulk barrier phototransistors device is more suitable for high gain and high speed infrared photo detecting applications.

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