懸浮式閘極場效應電晶體應用於梳狀致動器之位移感測

Displacement Sensing for Comb-Drive Actuators Using Suspended Gate Field-Effect Transistors

林東緯(Tung-Wei Lin)

指導教授 ： 陳榮順 ； 侯帝光

國立清華大學/工學院/動力機械工程學系/碩士(2006年)

摘要

本研究提出之位移量感測機制，乃是利用一具有懸浮式閘極結構之場效應電晶體，整合於微機電系統之中，提供靜電式梳狀致動器之位置迴授訊號。以本研究中提出之懸浮式閘極場效應電晶體進行位移量感測，其優點為架構單純、僅佔少許晶片面積，且易於整合於單晶片系統之中。此感測元件之製程可與積體電路製程相容，有利於進行微機電結構與積體電路之整合。
懸浮式閘極電晶體的操作原理，乃是透過輸出之汲極電流而感測懸浮閘極之位移量。本研究呈現懸浮式閘極電晶體與靜電式梳狀致動器的設計與分析，並對於其運作機制以數值模擬軟體進行驗證。另外，本論文亦針對所提出之系統架構，提出理論模型，以描述不同情況下之電晶體輸出汲極電流與致動器位移的關係。並經過製程架構設計，將懸浮閘極電晶體與靜電梳狀致動器整合於單晶片上，分別以TSMC 2P4M 0.35 um CMOS-MEMS製程與自訂之表面微加工進行實作。

關鍵字

位移感測 ； 懸浮式閘極 ； 梳狀致動器 ； 微機電

並列摘要

In this study, a displacement sensing mechanism is proposed using suspended gate field-effect transistor (SGFET) and integrated with comb-drive actuators to provide a position feedback signal. By utilizing SGFET, the proposed method has advantages of reduced chip size, simplicity in sensing structure, and compatibility with CMOS-MEMS fabrication process.
The operating principle of SGFET is to sense the displacement of suspended gate via the output drain current. Design and analysis for SGFET and comb-drive actuators are presented. A sensing structure combining an SGFET with a comb-drive actuator is proposed, with two models describing the linear and nonlinear drain current of SGFET. Numerical simulation is carried out to investigate the relationship between drain current of SGFET and displacement of comb-drive actuator. To demonstrate the proposed sensing mechanism, the integrated device on a single chip was implemented using both TSMC 2P4M 0.35 um CMOS-MEMS fabrication process and a customized surface micromachining process.

並列關鍵字

displacement sensing ； suspended gate ； comb-drive actuator ； MEMS ； field-effect transistor

參考文獻

[1] W. C. Tang, T. H. Nguyen, and R. T. Howe, “Laterally driven polysilicon resonant microstructures,” Sensors and Actuators, A: Physical, vol. 20, pp. 25-32, 1989.

[2] T. Harness and R. R. A. Syms, “Characteristic modes of electrostatic comb-drive X-Y microactuators,” Journal of Micromechanics and Microengineering, vol. 10, pp. 7-14, 2000.

[3] C. Marxer, P. Griss, and N. F. de Rooij, “Variable optical attenuator based on silicon micromechanics,” IEEE Photonics Technology Letters, vol. 11, pp. 233-235, 1999.

[4] W. H. Juan and S. W. Pang, “High-aspect-ratio Si vertical micromirror arrays for optical switching,” Journal of Microelectromechanical Systems, vol. 7, pp. 207-213, 1998.

[5] M. A. Haque, M. T. A. Saif, “Microscale materials testing using MEMS actuators,” Journal of Microelectromechanical Systems, vol. 10, pp. 146-152, 2001.