薄膜電晶體磁場感測器之研究

Abstract

現今的薄膜電晶體(TFT)已經發展許多年，製程技術可以說相當成熟，由於使用成本低廉的玻璃基板加上低溫製程的技術，因此目前薄膜電晶體被廣泛的應用於液晶螢幕的開關。然而，從近一、兩年的國外研究報告來看，許多薄膜電晶的感測應用逐漸浮出檯面，甚至有些薄膜電晶體的感測器已經有商業產品。本篇論文中，我們將利用薄膜電晶體結合磁場感測原理來實現霍爾效應感測器(Hall effect sensor)。整個元件製程溫度跟一般薄膜電晶體依樣都控制在600度以下。此外，我們將針對不同幾何結構的薄膜電晶體來分析各種感測元件的霍爾電壓(Hall voltage)模態，對於不同結構所得到的霍爾電壓(Hall voltage)、電壓偏移(offset)也將做一個深入的探討。藉由各種不同結構元件的設計、製作、量測到分析，我們可以獲得最佳化的磁場感測元件。

Nowadays TFT has developed for many years, and its fabricating technic is very mature. Due to using low-cost glass substrate and low-temperature fabrication technology, TFT has widespread application to use in switching devices of LCD. However, from the latest foreign research reports, many applications of TFT has emerged, and some commercial products of TFT application has appeared. In this thesis, we will develop a new Hall Effect sensor by using thin film transistor integrated with magnetic sensing principle. In the whole device fabrication, the processing temperature is been controlled below 600 degrees as well as other conventional TFT. In addition, we will analyze Hall voltage mode of magnetic sensors by use of various geometries of TFT. We also do a intensive discussion about Hall voltage and Bias offset due to different structures. By way of various geometry designs, device fabrication, characteristic measurement, we will be able to obtain optimal magnetic sensing devices.