電子顯微鏡開始發展使用以來，底片一直被用來記錄穿透式電子顯微鏡(Transmission Electron Microscopy，TEM )之電子影像。目前廣泛使用於穿透式電子顯微鏡的數位化影像裝置為慢速掃描電荷耦合裝置(Slow Scan Charged-coupled Device，SS CCD)，最早於1980年代開始使用於電子顯微鏡系統，使電子顯微鏡開始可以取得即時、有效率與大量的數位化影像。以閃爍體配合電荷耦合元件的非直接影像偵測系統(Indirect Imaging Detection System)，因閃爍體需先將電子影像轉換成光子影像，以避免輻射損傷與電荷飽和，再經由電荷耦合元件擷取產生影像，其先天的性質，限制了空間與時間解析(Spatial and Temporal Resolution)、效率(Efficiency)及影像拍攝速度(Frame Rate)。因此，發展有別於傳統底片與電荷耦合元件的直接影像偵測系統(Direct Imaging Detection System)，將矽微條偵檢器(Silicon Strip Detector，SSD)應用於穿透式電子顯微鏡的數位化影像拍攝被提出，矽微條偵檢器具備二維位置解析能力、空間解析度佳以及影像取得速度快等優點，可以達到穿透式電子顯微鏡之數位影像需求。
矽微條偵測器相較於同為矽偵測器一族之像素偵測器(Pixel Detector)具有結構簡單、電路數量大幅減少以及製作成本較低等優勢，但當多點訊號同時產生時(Multi-hits Events)，矽微條偵測器無法辨識訊號的真正位置。因此，本研究提出單面矽微條像素偵檢器(Single-sided Silicon Strip-pixel Detector)做為直接電子影像偵測裝置，設計金屬導線的排列方式以提升當多點訊號同時產生的位置分辨力，避免產生誤判(Ghost Images)現象。因同時具備矽微條偵測器的電路數量少與像素偵檢器的精確位置分辨力特色，所以命名為矽微條像素偵檢器。
本研究使用高阻值、N-doped、厚度250 μm的4吋矽基材，配合單面微機電製程技術，薄型化的設計，縮短其偵測電子束時所需的反應時間；線寬的設計，決定偵檢器的空間解析度；透過離子佈植的能量、劑量與退火參數的調整，提升偵檢器中P-N接面的性質；於主動區外圍設計保護環(Guard Ring)，降低元件的漏電流與提升崩潰電壓。
元件之電性量測結果為：暗電流為0.3 pA，崩潰電壓為-120 V，漏電流大小約為2.3 μA。增加保護環設計，漏電流減少3.48倍，且崩潰電壓變大75 V，證實可以有效地降低漏電流和提升崩潰電壓。藉由掃描式電子顯微鏡之電子束進行測試，得知偵檢器的能量動態範圍最小為5 keV，且30 keV尚未達到飽和，電流動態範圍最小為15.1 pA，至3.7 nA尚未達到飽合(15 keV)。在30 keV，Spot Size 70的電子束照射下，偵檢器全空乏時的訊噪比為3.12。經過理論計算，在30 keV下，求得電荷收集效率為0.703，偵檢器之檢測量子效率(Detective Quantum Efficiency，DQE)為0.016，影像拍攝速度為0.7 ms。將元件表現測試和估算結果與穿透式電子顯微鏡之偵檢器需求比較，認為將矽微條像素偵檢放置於穿透式電子顯微鏡中做為直接影像偵檢器應為可行。

From the early times of the electron microscopy, film has been used for recording the electron images in TEM. A standard detector option commonly used instead of film is the charged coupled device (CCD), which was first used in electron microscopy in the late 1980s. The CCD systems have enabled the immediate access to images in real-time, and have significantly increased throughput in the electron microscopy field. The CCD camera system is an indirect imaging detection system because the CCD will suffer from radiation damage and charge saturation during direct exposure of electron beam in TEM. A scintillator is thus needed to convert the electron image to a photonic image, which is then relayed to the CCD cameras for image acquisition. Hence, indirect imaging detection system have some inherent restrictions, including spatial and temporal resolution, efficiency and frame rate. In order to improve performance of electron detection systems, the application of silicon strip detector in TEM as a direct imaging systems was proposed. The application of silicon strip detector in TEM can meet the requirements for two-dimensional position sensitivity, spatial resolution and frame rate with direct sensing.
Compared to pixel detector like CCD, silicon strip detector has advantages of simple structure, less number of readout circuits and lower manufacturing complexity. But silicon strip detector has one major issue, ghost images, which is unavoidable. If more than one particle hits the silicon strip detector, the measured particles position is no longer unambiguous and ghost hits appear. In this work, we proposed a direct electron detector with unique readout metal strip arrangement, called silicon strip-pixel detector, to relieve multi-hits induced ghost image problems and greatly reduce the number of readout circuits compared with pixel detector. Owing to characteristics integration of silicon strip detector and pixel detector, it was called silicon strip-pixel detector.
The silicon strip-pixel detector is fabricated by single-sided process on high resistivity n-doped 4 inch diameter silicon wafer with a thickness of 250 μm. The pitch of strips determines the spatial resolution of the detector. The performance of P-N junction can be obtained by fine-tuning of implantation energy, dose and annealing parameters. The guard rings are designed around the active area to reduce leakage current.
The dark current of silicon strip-pixel detector is 0.3 pA, breakdown voltage is -120 V and leakage current is 2.3 μA. The detector with guard rings design can greatly reduce leakage current with 3.48 times and increase breakdown voltage of 75 V compared with detector without guard ring. The threshold energy of detector sensitivity is 5 keV, minimum signal current is 15.1 pA and signal to noise ratio (in full depletion) is 3.12. According to theoretical calculations, charge collection efficiency is 0.703, DQE is 0.016 and theoretical frame rate is 0.7 ms per frame. The strip-pixel detector can meet the generic requirements for direct electron imaging system and has great potential to be used as imaging sensor in TEM.

[1] M. Krammer, "Semiconductor tracking detectors in e+e− vertex detectors," Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, vol. 379, pp. 384-389, 1996.
[2] D. B.Williams and C. B. Carter, "Transmission Electron Microscopy A Textbook for Materials Science," Springer, 2009.
[3] "http://barrett-group.mcgill.ca/tutorials/nanotechnology/nano02.htm."
[4] "http://en.wikipedia.org/wiki/Photostimulated_luminescence."
[5] G. Y. Fan, D. G. Dunkelberger, and M. H. Ellisman, "Performance of thin foil scintillating screen for transmission electron microscopy," Ultramicroscopy, vol. 55, pp. 7-14, 1994.
[6] 鮑忠興 and 劉思謙, "近代穿透式電子顯微鏡實務," 滄海出版社, 2012.
[7] G. F. Knoll, "Radiation Detection and Measurement," John Wiley & Sons, 2010.
[8] "http://web.stanford.edu/group/scintillators/scintillators.html."
[9] J. P. Ponpon, "Semiconductor detectors for 2D X-ray imaging," Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, vol. 551, pp. 15-26, 2005.
[10] S. M. Sze and M. K. Lee, "Semiconductor Devices Physics and Technology," John Wiley & Sons, 2011.
[11] S. S. Li, "Semiconductor Physical Electronics," Springer, 2006.
[12] H. Becker, T. Boulos, P. Cattaneo, H. Dietl, D. Hauff, P. Holl, et al., "New Developments in Double Sided Silicon Strip Detectors," IEEE Transactions on Nuclear Science, vol. 37, pp. 101-106, 1990.
[13] J. C. Fontaine, S. Barthe, J. P. Ponpon, J. P. Schunck, and P. Siffert, "Single sided x-y position sensitive silicon strip detector a different approach," Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, vol. 348, pp. 428-430, 1994.
[14] N. Sawamoto, Y. Fukazawa, T. Ohsugi, H. Ohyama, H. Tajima, and K. Yamamura, "Development of a two-dimensional strip radiation sensor fabricated with normal silicon processes," Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, vol. 579, pp. 628-632, 2007.
[15] G. Moldovan, X. Li, P. Wilshaw, and A. Kirkland, "Thin silicon strip devices for direct electron detection in transmission electron microscopy," Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, vol. 591, pp. 134-137, 2008.
[16] S. O. Kasap, "Principles of Electronic Materials and Devices," McGraw-Hill, 2006.
[17] H. Spieler, "Semiconductor Detector Systems," Oxford Science Publications, 2005.
[18] C. Broennimann, E. F. Eikenberry, B. Henrich, R. Horisberger, G. Huelsen, E. Pohl, et al., "The PILATUS 1M detector," Journal of Synchrotron Radiation, vol. 13, pp. 120-30, Mar 2006.
[19] Z. Li, W. Huang, and L. J. Zhao, "Study of the correlation between the cutting edge current breakdown and the simulated lateral electrical field boundary in high resistivity silicon detectors with multi-guard ring structure," IEEE Transactions on nuclear science vol. 47, 2000.
[20] 曹正翰 and 洪志旺, "低漏電流與高崩潰電壓大面積矽偵測器製程之研究," 國立中央大學 碩士論文, 2001.
[21] "http://www.ndl.narl.org.tw/web/department/cfteam/docs/devices/T19_B.pdf."
[22] "http://en.wikibooks.org/wiki/Microtechnology/Additive_Processes."
[23] A. V. Gostev, S. A. Ditsman, V. V. Zabrodskii, N. V. Zabrodskaya, F. A. Luk’yanov, E. I. Rau, et al., "Characterization of semiconductor detectors of (1–30)-keV monoenergetic and backscattered electrons," Bulletin of the Russian Academy of Sciences: Physics, vol. 72, pp. 1456-1461, 2008/11/01 2008.
[24] G. E. Lloyd, "Atomic number and crystallographic contrast images with the SEM a review of backscattered electron techniques," Mineralogical Magazine, vol. 51, pp. 3-19, 1987.
[25] 周皇吉 and 蔡加春, "平滑式空間濾波器為架構之電流模式影像感測器設計," 國立台北科技大學 碩士論文, 2005.
[26] 葉宛亭 and 曾繁根, "應用於TEM之薄型化雙面矽微條偵檢器研製," 國立清華大學 碩士論文, 2011.