電容式超音波換能器與具極零點補償之轉阻放大器整合設計

本論文實現一個應用於生醫影像整合電容式超音波換能器與具極零點補償之轉阻放大器。提出利用標準CMOS製程實現的CMUT架構，並在單一晶片上整合了前端放大器。其中實現CMUT方式中僅利用了單一道濕式蝕刻的方式即能完成結構釋放，並且由於我們成功的利用標準CMOS製程實現CMUT，可以將前端電路整合在單一晶片上，避免寄生效應導致感測訊號會有較低的解析度。超音波影像的應用聲頻介於1MHz~10MHz，而轉阻放大器具有連續時間訊號處理的特性，高增益、架構簡單以及適用於此頻寬範圍內皆符合本次超音波影像系統的需求。論文中提出極零點補償的技巧，使得放大器在低功率消耗的情況下達到所需規格；利用電流源校正的方式確保在P.V.T變異下仍能正確的補償極零點。本晶片使用TSMC 0.18 um CMOS Mixed Signal RF General Purpose Standard Process FSG Al 1P6M 1.8&3.3V實現，並自行完成結構後製程，主動區面積為1.93mm2。在1.8V的供應電壓下，此超音波影像系統其總功率消耗約為0.37~0.45毫瓦。

關鍵字

電容式超音波換能器；微機電系統；轉阻放大器；極零點補償

並列摘要

This paper presents a design of Transimpedance Amplifier with pole-zero cancellation and integrated Capacitive Micromachined Ultrasonic Transducer (CMUT) for medical imaging. CMUT has been implemented in the standard CMOS process, and a Transimpedance amplifier (TIA) is integrated in a single chip. The post-CMOS fabrication requires only one wet etching processing. The monolithic integration avoids the parasitic capacitance and enhances the single-to-noise ratio. The active frequency is between 1MHz to 10MHz for ultrasonic medical imaging and TIA is continuous-time process, high gain, simple architecture and suited bandwidth for this. The pole-zero cancellation made TIA meet the specification with lower power consumptions was also presented. Current source calibrated make sure the pole-zero cancellation correctly in process, voltage, temperature variations. This chip was fabricated in a TSMC 0.18 um CMOS Mixed Signal RF General Purpose Standard Process FSG Al 1P6M 1.8&3.3V, and fabricates the post-process in MSIC lab .The active area is 1.93mm2. The ultrasonic medical imaging system consumes 0.37~0.45mW at 1.8-Vpower supply.

並列關鍵字

CMUT ； MEMS ； TIA ； Pole-zero cancellation

參考文獻

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[4] G. Percin and B. T. Khuri-Yakub, “Piezoelectrically Actuated Flextensional Micromachined Ultrasound Transducers-I: Theory,” IEEE International Ultrasonics Symposium, Vol. 49, No. 5, pp.573-584, 2002.

[5] G. Percin and B. T. Khuri-Yakub, “Piezoelectrically Actuated Flextensional Micromachined Ultrasound Trandducers-II: Fabrication and Experiments,” IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, Vol. 49, No. 5, pp.585-595, 2002.

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國際替代計量

電容式超音波換能器與具極零點補償之轉阻放大器整合設計

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