以CMOS製程技術製作延伸式場效電晶體及其訊號處理積體電路之研究

Study of the Extended Gate Field Effect Transistor (EGFET) and Signal Processing IC Using the CMOS Technology

覃永隆(Yuan-Lung Chin)

指導教授 ： 熊慎幹

中原大學/工學院/電子工程研究所/博士(2001年)

https://doi.org/10.6840/cycu200100400

摘要

以CMOS製程技術製作延伸式場效電晶體及其訊號處理積體電路之研究研 究 生: 覃永隆 指導教授: 熊慎幹 博士 中文摘要 離子場效電晶體最先發表於1970年，由於其具體積小、反應快速及製程相容於金氧半場效電晶體半導體製程等優點，而具有成為化學及生醫感測元件的潛力，目前已受到廣泛的研究。在我國晶圓代工的技術已臻於世界的水準，如何在即有的優勢，結合半導體標準製程，製作出微感測器及電路的單晶片是我們所應努力研發的方向。因此技術的成功，可帶動許多的產業，由於標準製程具有許多的優點，如量產，製程的良率高，可降低成本。而生產的成品體積很小，可集各感測器及相關的電路於單一晶片上，甚至做成陣列的型式，應用的層面相當廣泛。 本論文即是研究如何將離子感測器以CMOS半導體製程製作。在研究的結果中，發現延伸式閘極架構的離子感測器，最能吻合現有的製程。以此型式製作離子感測器，不需額外的光罩或蝕刻等後段的加工製程，只要用濺鍍機鍍上感測薄膜，再經封裝即可完成。在選擇薄膜的過程中，以模擬及實驗的結果，得知其感測膜的內阻值不可過高。研究發現氧化錫及氮化鈦是可運用於離子感測器的感測膜。量測結果顯示，以此薄膜為感測材料之感測元件，擁有極佳之感測特性。為達到感測器及讀出電路於同一晶片的目的，本論文研發三種適用於離子感測器的讀出電路，並同時製作於同一晶片中，使成為單晶片的型式。最後，亦提出各電路的適用層面。 由於離子感測器會隨溫度的變化而影響其輸出，進而減少其應用的範圍。所以探討此種感測元件之溫度特性及補償方法。在此研究主題中，首先對離子感測器的溫度特性，分別研析出元件中會隨溫度改變的變因。最後針對其變因各採取補償的方式，而提出在同一晶片下製作二極體溫度感測器的結構，運用延伸式離子感測器正向的溫度係數及二極體負向的溫度係數，再經由加總電路將兩訊號相加，而達到溫度補償的目的。 離子感測器會受溫度及光影響而造成不穩定輸出的缺點，為解決此問題，設計同時具有可偵測酸鹼值、溫度及光強度的多感測器晶片。透過特殊設計的讀出電路，可使整體的晶片體積縮小，且效能高。此多感測器的單晶片，可做為離子感測器在溫度及光方面的補償外，亦可延伸做為生醫感測器的應用。關鍵詞: 離子感測場效電晶體、CMOS標準製程、氧化錫、氮化鈦、讀出電路、溫度特性、多感測器晶片、生醫感測器。

關鍵字

多感測器晶片 ； 讀出電路 ； CMOS標準製程 ； 生醫感測器 ； 離子感測場效電晶體

並列摘要

Study of Extended Gate Field Effect Transistor (EGFET) and Signal Processing IC Using CMOS technology Student : Yuan-Lung Chin Advisor : Dr. Shen-Kan HsiungDepartment of Electronic Engineering Chung-Yuan Christian UniversityAbstract A description of the ion sensitive field effect transistors (ISFET) was first published in 1970 (Bergveld 1970). More recently the ISFET has been studied extensively because it’s advantages such as small size, rapid response and more importantly, the possibility of the manufacturing using the MOSFET process. Moreover, it has extended applications in bioelectric and biosensors. In our country, the CMOS IC foundry industry has achieved world class technology levels. Using the advantageous position to produce micro sensors and circuits using the CMOS IC standard process is our current objective. This technology must be studied and developed. The potential advantages of this process including mass production, high-yield and low cost will bring these advantages to many industries. These small sized products can integrate sensors and readout circuits into the same chip to produce an array. The aim of this study was to fabricate the ion sensors using the standard CMOS process. Producing an extended gate field effect transistor (EGFET) structure to suit this process was also necessary. This EGFET structure must require no extra mask or post-process etching. In addition to dielectric material used as the pH sensing layer, conducting material such as SnO2, TiN applied using r. f. sputtering have also been shown to be a sensitive and inert alternative material. According to the experimental results, it exhibited good response and performance. From the simulation and experimental results, the inner resistor of sensing membrane must not be too large. Three kinds of readout units for the EGFET were tested for the application in a single chip.Investigations have demonstrated that EGFETs have a large thermal instability, which leads to inaccuracy in measurements. It is often necessary for EGFETs to be used under thermostatic conditions to ensure the necessary accuracy. Since this is not convenient for many applications. It is important to investigate the thermal behavior of EGFETs to determine effective methods to improve their stability. In this study, we report on a method for the EGFET temperature compensation. A summation circuit was used to combine an EGFET and a p-n temperature sensor diode. Using the p-n diode negative temperature coefficient and the EGFET positive temperature coefficient together, the two sensors can reduce the temperature characteristics of the ISFET. In order to simplify the sensor fabrication into one chip, the EGFET, p-n diode and readout circuits were produced using a CMOS standard IC process.The ISFET pH sensors have problems such as thermal instability and are easily affected by light. With the aim of solving these problems, we designed a chip that includes a pH sensor, temperature sensor, photo sensor and readout circuits. This chip has the ability to readout three kinds of data simultaneously and compensate for the EGFET pH sensor sensitivity to the temperature and light. In order to reduce the chip area, the novel readout circuits were specially designed to reduce the chip area. They are not only used increasingly for a variety of purposes for the EGFET temperature and light compensation, but also for chemical, medicine and biosensor industry applications. Keywords: Extended Gate Field Effect Transistor (EGFET), CMOS Standard Process, SnO2, TiN, Readout Circuit, Temperature Characteristic, Multi Sensor, Biosensor

並列關鍵字

Readout Circuit ； Extended Gate Field Effect Transistor (EGFET) ； Biosensor ； CMOS Standard Process ； Multi Sensor

參考文獻

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