矽基板與薄膜電晶體磁場感測器之研究

Abstract

在本論文中我們研製並測試兩種不同結構的三度空間矽基板磁場感測器, 其中, 第二種結構具有較深有效井深且對對電壓輸出形式能同時增加靈敏 度及對稱性, 而對差電流輸出形式則只有使磁場與表面平行的靈敏度 增 加。為增加靈敏度的對稱性, 鈷和鎳兩種鐵磁性材料被鍍在晶片背面以增 加垂直晶片方向的靈敏度, 經實驗證實增加了近十倍, 且得到靈敏度對稱 性相當理想。另外, 我們利用兩個分開汲極結構薄膜電晶體做磁場感測元 件並量測其特性, 發現其靈敏度隨不同閘極電極電壓有一最大值。 Magnetic field sensors which exploit the galvanomagnetic ef- fect due to the Lorentz force on charge carriers have been pres- ent for many years.In this study,magnetic field sensors of two structures have been implemented and optimized in order to inve- stigate the possibility of increasing the symmetry of device se- nsitivities in three directions for 3-D magnetic- field sensors. For Hall voltage output format,the p+ well of the second struct- ure incteases the sensitivities in x-,y- and z-directions and improve the symmtry of sensitivities.For differential current output format,the p+ well can only increase the sensitivities for an in-plane magnetic-field applied. To improve the magnetic responses to magnetic field perpendicular to the , wafer surface ,Co-Ni coating is used and the sensitivities for a magnetic field applied perpendicularly to the wafer surface are ten times more than that of a uncoated device.Further,a 2-drain have been implemented for TFT magnetic field sensors. Experimental results for this type of sensors indicate that there is a maximum value of sensitivity for various gate voltage.