熱阻式熱偵檢元件之矽微細加工結構研究

Abstract

本文對微加工技術製作之熱敏阻式紅外線偵測陣列元件進行結構及製 程之設計,我們分析浮板材料.應力.隨溫度變化特性;經量測到之偵檢度 為4.2E5, 本偵檢器結構使用矽微細加工技術製作, 這些特性和紅外線偵 檢元件結構及每一單位像素熱阻絕結構有關係,第一個特性是使用複晶矽 當作薄膜熱感材料用以偵測紅外線,我們量測複晶矽電阻率與TCR的關係, 第二個特性是使用矽微細加工技術形成浮橋結構以阻絕熱散失,製程的良 率可達95%,因為複晶矽在傳統大型矽積體電路製程中普遍使用,這項選擇 得以順利使用現有大型矽積體電路製程製作影像感測器,藉此可以得到不 須降溫,價格低廉的紅外線攝影機 o This thesis presents the design of structure and process for bolometer arrays with micromachining technology. We analyze properties of temperature dependance of material and stress.The measured specific detectivity(D*) is4.2E5. This sensor has a structure using micromachining technology.These features concern the structure of the infrared detector, and the thermal isolation structure in a pixel. The first feature is the use of a thin film resistive bolometer made of polysilicon as the infrared detector. We show the measured dependence of the TCR on the resistivity of polysilicon. The second feature is a microbridge structure for the thermal isolatiln is made in each pixel by using the micrmachining technology. The yield of process can reach 95%. Since polysilicon is generally used in the conventional Si-LSI process, this choice of detector material makes it possible to manufacture the image sensor using only current Si-LSI facilities, and realize a low cost uncooled infrared camera.