含0.25μm BCD製程中接面場效電晶體之微機電麥克風讀出電路

A MEMS microphone readout circuit with on-chip JFET in 0.25μm BCD process

莊祖維

指導教授 ： 徐永珍

國立清華大學/電機資訊學院/電子工程研究所/碩士(2014年)

摘要

近年來，隨著CMOS-MEMS製程的進步，微機電麥克風取代了傳統駐極體式麥克風成為主流，應用於不同的消費性電子產品上。由於微機電麥克風的電容變化相當微小，因此需要低雜訊的讀出電路將訊號放大並讀出。
本論文於0.25μm BCD製程下設計一接面場效電晶體(JFET)元件當作讀出電路的輸入緩衝器，並與低雜訊放大器整合在一起，相較於MOSFET，JFET有著較低的閃爍雜訊。藉由JFET低雜訊的特性，將閃爍雜訊最小化，改善傳統上使用大面積MOSFET降低閃爍雜訊而造成感測器訊號衰減的問題。
為驗證JFET之可行性，設計另一組以MOSFET作為輸入緩衝器的對照組做比較。由量測結果證實，採用JFET版本之架構，可降低閃爍雜訊，相比於MOSFET版本之架構有較小的輸入相關雜訊。

關鍵字

接面場效電晶體

並列摘要

In recent years, with the progress of CMOS-MEMS technology, MEMS microphone gradually replaced the traditional Electret Condenser Microphone (ECM) and became the mainstream in consumer electronic products. Due to the small capacitance change single from MEMS microphone is quite small, a low noise readout circuit is needed to amplify the signal.
Conventionally, the MOSFET with large size was used to reduce flicker noise, but it also caused the degradation of sensor signal. JFET has lower flicker noise than MOSFET so we designed a JFET as the input buffer for readout circuit to solve the problem and integrated the low noise amplifier with it. This IC was fabricated with TSMC 0.25μm BCD process.
In order to verify the feasibility, we designed another circuit in which the JFET input buffer was replaced by a MOSFET as control group of samples. Confirmed by the measurement results, using JFET in the amplifier can reduce flicker noise, and compared to the MOSFET version obtain lower input referred noise.

並列關鍵字

JFET

參考文獻

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