非晶矽薄膜電晶體作為光感測元件及電路之研究

Abstract

非晶矽薄膜電晶體由於它的高光感測性以及較易製作於大面積上，在 主動矩陣液晶顯示器以及偵測器上受到廣泛的注意。之前的研究指出，ㄧ 些使用薄膜電晶體的感測機構都已經被論証討論。然而，大部分傳統型的 光感測器都是用外部的分離元件去裝置的，所以會造成額外的成本與設計 上的複雜度。 為了研究上述的這個課題，增加畫素開關薄膜電晶體的速度與光電晶 體的動態偵測範圍。在本計畫中，我們設計多種類型的薄膜電晶體元件， 藉由不同結構亦或閘極電壓的調整，我們可以依照需求決定光產生電流的 效率區域多寡。同時，所設計的光電晶體在不同操作區域的不同偵測能力 的特性可被用做動態偵測範圍中提升訊號雜訊的比值。並且此系統的特殊 設計結構亦可用作偵測背光源。並且由於整個製程並沒有額外的流程，這 對我們要將光感測器整合是相當有幫助的。同時，我們希望藉由計畫的執 行能達到卓越的研究成果，能更提昇我國技術水準，趕上世界的技術水平， 衍生更具附加價值的面板產品。

Hydrogenated amorphous silicon thin film transistors (a-Si:H TFTs) receive extensive application in active matrix liquid crystal display (LCD) and sensors due to its high photo sensitivity and ease of deposition across large area substrates. It was reported that some sensing functions using TFTs were already also demonstrated. However, most of the conventional ambient light sensor systems were implemented by external discrete devices which cause additional cost and the design complexity. In addition to the research for issues above, to increase the speed of pixel switching TFT, cause a large drop in the dynamic range of photo transistor. In this project, we design some kinds of different type TFT devices. We can make an alteration depletion length to control effective region of photo-excited leakage current from adjustment of different type device structures or gate voltages. Meanwhile, the difference sensing capability of designed photo transistor from the dark to the bright region by itself is adaptive to increase signal-to-noise ratio (SNR) for wide dynamic range. The system also can be used to sense back light illumination. This method does not need novel device process development and can be implemented on to panel helpfully. Furthermore, based on the achievements in these projects, we will help the panel industry in Taiwan to catch up the world.