隨著互補式金氧半導體製程技術之演進，影像感測器元件可越作越小，容許感測器往高畫素的趨勢發展。摻雜濃度越來越高，使得像素的靈敏度下降。隨著感測器元件越來越小，光線散射導致之交叉干擾會更嚴重，所以光學部分需要加入考量。因此本論文主要有兩個工作，第一、從像素佈局著手，藉由改變像素光二極體佈局來達到特性最佳化，從實驗量測結果得知，轉角為圓弧形之光二極體佈局設計，暗電流較低。第二、提出一個二維的像素光學模型，針對應用於感測器的微透鏡與相關光學問題作深入探討。並透過MEDICI軟體作光學與電性的綜合模擬，藉由微透鏡參數與光二極體面積大小的改變來探討其像素特性變化。並以該像素模型為基礎，提出光點彩色濾光法，用來取代彩色濾光陣列。除此之外，本論文亦模擬像素之間交叉干擾的情形，並對於不同介質阻隔斜射光的效果作探討。模擬結果得知，以金屬層阻擋斜射光的效果最佳。從該模型可以了解像素裡光線入射的情形，並且可作為實際像素與微透鏡設計的輔助工具。

Due to the CMOS technology scaling, the smaller imaging pixels provide higher resolution application. As doping concentration in a photodiode increases, the sensitivity of a pixel becomes lower. The cross-talk effect due to light scattering to adjacent cells is getting worse as pixel size reduces. Therefore, the optical issue should be considered carefully. In this work, two major subjects are investigated. First, modifying photodiode layout to achieve better pixel performance. From the experiments results, rounded corner photodiode can achieve lower dark current. In addition, a two-dimensional optical pixel model is proposed to study the micro-lens design and cross-talk effect due to light scattering. By optical and electrical simulation using MEDICI program, the pixel performance when micro-lens parameters and photodiode area design is discussed. Light Spot Color Filtering based on this model is proposed to replace Color Filter Array application. This model also allows for cross-talk simulation and cross-talk suppression effects as a result of different blocking materials. From simulation results, the metal can block the obliquely incident light efficiently. This study can help sensor designers not only to understand the ray trace in a sensor pixel but also serve as a reference for pixel and micro-lens design.

[1] E. R. Fossum, “CMOS image sensors: Electric camera-on-a-chip,” IEEE Trans. Electron Devices, vol. 44,pp.1689-1698, Oct. 1997.
[2] H. S. P. Wong, “CMOS image sensors–Recent advances and device scaling considerations,” in IEEE IEDM Tech. Dig., 1997, pp.201-204.
[3] Sunetra K. Mendis, Eric Fossum, ”CMOS Active Pixel Sensor for Highly Integrated Imaging Systems,” IEEE J. Solid-State Circuits, vol. 32, No. 2, pp. 187-197, Feb. 1997.
[4] H. Rhodes, G. Angranov et al., “CMOS Imager Technology Shrinks and Image Performance,” Microelectronics and Electron Devices, 2004 IEEE Workshop on 2004 pp.7 - 18.
[5] Chung-Yu Wu et al., “Design, Optimization, and Performance Analysis of New Photodiode Structures For CMOS Active-Pixel-Sensor Imager Applications,” IEEE Sensor Journal, vol. 4, No. 1 ,Feb. 2004.
[6] Igor Shcherback and Orly Yadid-Pecht, “ Photoreponse Analysis and Pixel Shape Optimization for CMOS Active Pixel Sensors,” IEEE Trans. Electron Devices, vol. 50, No. 1,Jan. 2003.
[7] Igor Shcherback and Orly Yadid-Pecht, ”Predication of CMOS APS Design Enabling Maximum Photoresponse for Scalable CMOS Technologies,” IEEE Trans. Electron Devices, vol. 51, No. 2, pp.279-282, Feb.2004.
[8] Weiquan Zhang and Mansun Chan, ”Properties and Design optimization of Photodiodes Available in a current CMOS Technology,” IEEE Hong Kong Electron Devices Meeting, pp 22-25, 1998.
[9] Igor Shcherback, Alexander Belenky and Orly Yadid-Pecht , “Empirical dark current modeling for Complementary metal oxide semiconductor active pixel sensor,” Society of Photo-Optical Instrumentation Engineers, 2002.
[10] Gennadiy Angranov et al., “Crosstalk and Microlens Study in a Color CMOS Image Sensors,” IEEE Trans. Electron Devices, vol. 50, Issue 1 Jan 2003.
[11] Masayuki Hurumiya et al., “High Sensitivity and No-Crosstalk Pixel Technology for Embedded CMOS Image Sensor,” IEEE Trans. Electron Devices, vol. 48, No. 10, Oct. 2001.
[12] Dun-Nian Yaung et al., “Air-Gap Guard Ring for Pixel Sensitivity and Crosstalk Improvement in Deep Sub-micron CMOS Image Sensor, “IEEE Electron Devices Meeting, 2003.
[13] Peter Catrysee and B. Wandell, “Optical Efficiency of Image Sensor,” Optical Society of America, 2002.
[14] Avant! Corporation , Medici4.1 User’s Manual, Fremont, CA, Jul. 1998.
[15] H. D. Lee and J. M. Hwang, “Accurate Extraction of Reverse Leakage Current Components of Shallow Silicided p+-n Junction for Quarter- and sub-Quarter-Micron MOSFETs, ”, IEEE Trans. Electron Devices, vol. 45, No. 8, August 1998.
[16] Foveon X3 Technology papers: Eyeing the Camera: Into the Next Century.
[17] New Semiconductors and materials: Characteristics and properties at Loffe Physico-Technical Institude ,Russian.