以微製程技術製備鋯鈦酸鉛焦電式微熱量感測器

本研究以微製程的方法來製作一紅外線焦電薄膜感測器，焦電薄膜材料選用sol-gel形式的鋯鈦酸鉛(PZT)來製備，並且旋鍍成膜後經700 ℃的高溫退火，使薄膜形成鈣鈦礦之晶格結構，感測晶片由Ni/Cr/PZT/Pt/Ti/SiO2/Si形成三明治結構，以此進行各項焦電特性與感測分析，接下來我們進ㄧ步討論工作面積與工作陣列規格之晶片對於紅外線的感測的影響，並分析出晶片特性的優劣，最後組裝外部硬體電路來穩定輸出訊號，並且使用Labview DAQ介面將系統連結至電腦，進而可直接在電腦上監控感測訊號的變化。本研究將量測介電常數、介電損失、漏電流密度、焦電係數、電壓感度、電流感度、等效雜訊功率、優值、比感測率等，來分析薄膜品質與晶片感測特性。由實驗結果得知，感測工作面積過大的試片，因薄膜常有過多的缺陷產生，導致短路而失去焦電特性。而相對於較無缺陷影響的試片中，當單位工作面積較小時有較佳之特性，由電壓感度公式下推論後，符合晶片感測度會因工作面積微小化而提高靈敏度。比較相同單位工作面積下之單一感測規格與陣列式感測規格的試片，其各項電性皆以陣列式的試片為佳，由於陣列式晶片將單一工作面積縮小，使得單元下焦電薄膜製備後更加完整，提供各項較佳的特性。比較所有實驗結果得知試片2(250×250 μm2，工作單元規格為2×2，總工作面積為250000 μm2)有最佳化的電特性，其εr=266 F/m、loss tanδ=0.022、γ=29.66 nC/cm2K、RV=134.2 V/W、RI=0.094 μA/W、FV=0.445×10-10Ccm/J、Fm=0.435×10-8Ccm/J、D*=9.81×103 cmHz1/2/W。其輸出訊號再經由電路處理與Labview顯示後，可以很明顯的觀察出輸出訊號在有無感測熱輻射能量的差異性，以得到熱量變化的感測目的。本研究可提供未來生物放熱實驗的熱量檢測，藉由微製程技術使晶片微小化，進而提升晶片感測的靈敏度，以期望可量測到微量的熱量變化，作為量測生物熱量釋出的溫度計。

關鍵字

鋯鈦酸鉛；焦電

並列摘要

In this thesis, we create pyroelectric infrared (IR) sensors of lead zirconate titanate (PZT) by Microfabrication method. The pyroelectric thin films were prepared by a modified Sol-gel method. A 700 ℃ annealing process realized the crystallization of the PZT thin films. The structure of PZT IR sensor was sandwich structure of Ni/Cr/PZT/Pt/Ti/SiO2/Si. When the fabrication of PZT sensors was completed, we examined the relations between characteristics and working area of PZT IR sensors. Subsequently, a circuit was constructed for stabilizing the output signal of the sensor. The output signal could be seen on the computer. Dielectric constant, dielectric loss, current leakage density, pyroelectric coefficient, voltage responsivity, current responsivity, noise equivalent power, figures of merit and specific detectivity have been measured for analyzing the performance of PZT IR sensors. The sensors with large working areas failed more easily to more impurities and defects. According to the responsivity equation, the sensitivity was raised with the miniaturization of the unit working area. From the results of the experiments, we found that better performances could be obtained with array type design under the situation of total working area. Our research accomplished the miniaturization of the PZT IR sensor to increase the responsivity sensitivity. We expect this sensor system to be applicable in microthermometric in the future.

並列關鍵字

pyroelectric ； PZT

參考文獻

[1] D.L. Polla, L. F. Francis, Ferroelectric Thin Films in Micro-electromechanical Systems Applications, MRS BULLETIN, pp. 59-65, 1996.

[4] E. Sawaguchi, T. Mitsuma, Z. Ishii, Double Hysteresis Loop of (PbXCa1-X)TiO3 Ceramics, J. Phys. Soc. Japan, Vol. 11, pp. 1298, 1956

[8] Y. Z. Chen, J. Ma, L. B. Kong, Seeding in sol-gel process for Pb(Zr0.52Ti0.48)O3 powder fabrication, Materials Chemistry and Physics, Vol. 75, pp. 225-228, 2002.

[11] D. Kim, T. Y. Kim, Microstructure control in MOCVD PZT thiin films, Materials Research Society Symposium-Proceeding, Vol. 433, pp. 213-224, 1996.

[12] H. Kanai, Y. Yamashita, Investigation of Factors Affecting Electrical Properties of PZT Thin Film Capacitors, International Symposium on Applications of ferroelectrics, pp. 121-124, 1998

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以微製程技術製備鋯鈦酸鉛焦電式微熱量感測器

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