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http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/61310
Title: | CMOS-MEMS電容式微機電系統超音波換能器製作與開發 Development of CMOS-MEMS Capacitive Micromachined Ultrasonic Transducers |
Authors: | Fang-Yu Lin 林芳伃 |
Advisor: | 田維誠(Wei-Cheng Tian) |
Keyword: | CMOS-MEMS,超音波,電容式微機電系統換能器,零偏壓, CMOS-MEMS,Capacitive Micromachined Ultrasonic Transducers (CMUTs),Zero-bias, |
Publication Year : | 2013 |
Degree: | 碩士 |
Abstract: | 本研究利用TSMC 0.35μm 2P4M CMOS-MEMS製程開發電容式超音波換能器(Capacitance Micromachined Ultrasonic Transducer ,簡稱CMUT),由於元件不耐高壓、介電層的充電效應,以及種種降低元件可靠度的因素,過去CMUT只能當作很好的超音波接收器,但發射超音波訊號並非易事。本研究藉由增厚絕緣層和由脈衝發射接收器(Pulser) 取代傳統上DC加上AC的CMUT發射驅動模式,使元件得以有效的發射的超音波訊號。此外,我們發現可以利用介電層易累積電荷的現象,改採Pulser來致動元件,使得致動元件時滯留的電荷能提供足夠的靜電作用力。在此操作狀況下,元件並不需要加偏壓,即可有良好的元件的靈敏度以及換能器效能。量測的結果證實,我們所開發出來的CMOS-MEMS CMUT其中心頻率大概7~8MHz,比例頻寬(Fractional Bandwidth)大約75%~85%,靈敏度為2.894mV/kPa,由商用Pulser PR5900(Panametrics Inc., Waltham, MA, USA)致動,其發射聲場大約為760kPa。此外我們也利用本團隊研發之CMUT進行超音波的應用實驗,像是非破換性檢測和線仿體掃描,都獲得不錯的應用成果。與目前其他團隊所開發出來的CMOS-MEMS CMUT比較,此元件除了具有較大的發射聲場具有較好的靈敏度,也有較佳的比例頻寬。而不需加偏壓的操作模式,也開啟了CMUT在超音波應用上另一個世代。 In this study, a zero-bias CMOS-based Capacitive Micromachined Ultrasonic Transducers (CMUTs) with high sensitivity is developed. The device is implemented with the TSMC 0.35μm CMOS-MEMS process. Driven by a commercial pulser, it is speculated that charges were injected into the charge traps in the CMUT and these temporarily stored charges provided a built-in electric field comparable to that created by an external DC bias. Therefore, our CMUTs can achieve great sensitivity without an external DC bias. When driven by a commercial pulser, the CMUTs generated ultrasound signals with a center frequency of 7-8 MHz, fractional bandwidth of 75-85%, and the acoustic filed of 760kPa. The sensitivity at receive was 2.9mV/kPa. It is successfully demonstrated that our developed CMUT-based system was able to image a coin. Compared with other CMOS-based CMUTs, our device generally has good sensitivity and wide bandwidth. To our knowledge, it is the first zero-bias CMUT device using commercial CMOS process reported in the literature. It is believed that several applications can be explored with our developed CMUTs. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/61310 |
Fulltext Rights: | 有償授權 |
Appears in Collections: | 生醫電子與資訊學研究所 |
Files in This Item:
File | Size | Format | |
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ntu-102-1.pdf Restricted Access | 2.51 MB | Adobe PDF |
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