臺灣博碩士論文加值系統

雪崩增益效應是透過讓電晶體在逆向偏壓下產生雪崩崩潰，進而達到增加載子的一種效應，此效應被廣泛地運用在小訊號的偵測。本論文透過分析雪崩增益效應的物理機制來模擬出特定結構下的增益與雜訊，並藉由模擬結果推論該結構理論上可以達到的各種效能參數，包括電子電洞的解離比率、相對應的暗電流、靈敏度以及增益頻寬積。
在理論與模擬基礎上，本論文將分別分析矽鍺與鍺光偵測器之效能參數，並比較兩者之差異。結果顯示鍺光偵測器由於暗電流過大而無法降低其靈敏度；而矽鍺光偵測器則可以透過改變結構達到改進其靈敏度及降低操作電壓之結果。

Avalanche multiplication effect is to amplify small signal by operating the pn-junction at breakdown voltage. In this thesis, we analyze the physics of avalanche breakdown, and try to get mean gain and noise factor by simulation. With simulated mean gain and noise factor, we can extract the ionization ratio, dark current, sensitivity, and gain-bandwidth product for a certain structure.
Base on theory and simulation, we will analyze both silicon-germanium and germanium based avalanche photodetector, and give a summary for these avalanche photodetector. The result shows that, germanium based avalanche photodetector owns large dark current when we operate at breakdown voltage, which gives bad sensitivity. In contrast, silicon-germanium avalanche photodetector can be improved by changing injection type and splitting absorption and multiplication region.

中文摘要 i
Abstract ii
Acknowledgment iii
Table of Contents iv
List of Figures vi
List of Tables vii
Chapter 1 Introduction 1
1.1 Photodetector and material 1
1.2 Avalanche photodetector 3
Chapter 2 Avalanche breakdown model 11
2.1 Dead space effect 11
2.2 Impact ionization 12
2.2.1 Ionization rate 12
2.2.2 Probability of impact ionization 13
2.2.3 Mean gain and noise factor 13
2.2.4 Ionization ratio 17
2.3 Dark current 21
2.3.1 Thermal dark current 21
2.3.2 Band to band tunneling dark current 21
2.4 Sensitivity 23
2.5 Gain-bandwidth product (GBP) 26
Chapter 3 Silicon based APD 28
3.1 UTC structure overview 28
3.2 Dark current 29
3.2.1 Theoretical derivation 29
3.2.2 Simulation result 33
3.3 Sensitivity 34
3.4 Gain-bandwidth product (GBP) 36
Chapter 4 Germanium based APD 37
4.1 Ku Hung’s device processing 37
4.2 Dark current fitting 38
4.3 Sensitivity 40
Chapter 5 Summary 42
References 43

[1] Saleh, B.E.A. and M.C, Fundamentals of Photonics, 1991.
[2] Chih-Kuo Tseng et al., “A High-Speed and Low-Breakdown-Voltage Silicon Avalanche Photodetector,,” IEEE Photonics Tech. Letters, vol. 26, no. 6, pp. 591-594, 15 Mar. 2014.
[3] Y. Kang et al., “Monolithic germanium/silicon avalanche photodiodes with 340 GHz gain-bandwidth product,” Nat. Photonics, vol. 3, no. 1, pp. 59-63, Jan. 2008.
[4] Solomon Assefa et al., “Reinventing germanium avalanche photodetector for nanophotonic on-chip optical interconnects,” Nature, vol. 464, pp. 80-84, 4 Mar. 2010.
[5] Virot, L.o., et al., “Germanium avalanche receiver for low power interconnects,” Nature communications, pp. 1-6, 18 Sep. 2014.
[6] Jaewoo Shim, et al., “Germanium p-i-n avalanche photodetector fabricated by point defect healing process,” OPTICS LETTERS, Vol. 39, No. 14, pp. 4204-4207, 15 July 2014.
[7] K. H. Chen, “Ge PIN Photodetectors and Study of the Avalanche Multiplication Effect,” National Tsing Hua University Library, 2014.
[8] H. T. Chen, et al, “High sensitivity 10Gb/s Si photonic receiver based on a low-voltage waveguide-coupled Ge avalanche photodetector,” OSA,Vol. 23, No. 2, pp. 815-822, 26 Jan. 2015.
[9] Sze, S.M. and G. Gibbons, “AVALANCHE BREAKDOWN VOLTAGES OF ABRUPT AND LINEARLY GRADED p‐n JUNCTIONS IN Ge, Si, GaAs, AND GaP,” Applied Physics Letters, pp. 111-113, 1966.
[10] Y. Okuto and C. R. Crowell, “Ionization coefficients in semiconductors: A nonlocalized property,” PHYSIGAL REVIEW B,VOLUME 10, NUMBER 10, p. 4292, 15 Nov. 1974.
[11] Majeed M. Hayat, et al, “Effect of Dead Space on Gain and Noise of Double-Carrier-Multiplication Avalanche Photodiodes,” IEEE TRANSACTIONS ON ELECTRON DEVICES, VOL. 39, NO. 3, pp. 546-552, Mar. 1992.
[12] R. McIntyre, “Multiplication noise in uniform avalanche diodes. Electron Devices,” IEEE Transactions on electron devices, pp. 164-168, 1966.
[13] R. G. Smith and S. D. Personick, “Receiver Design for Optical Fiber Communication Systems,” Topics in Applied Physics Vol. 39, pp. 89-160, 1980.
[14] J,J, Sakurai and Jim Napolitano, “Quantum Dynamics,” 於 Modern Quantum Mechanics second edition, 2011, pp. 110-116.
[15] E. O. Kane, “Zener Tunneling in Semiconductors,” J. Phys. Chem. Solids, vol. 12, pp. 181-188, 1959.
[16] Kuo-Hsing Kao et al., “Direct and Indirect Band-to-Band Tunneling in Germanium-Based TFETs,” IEEE Transactions on Election Devices, vol. 59, no. 2, pp. 292-301, Feb. 2012.
[17] R. B. Emmons, “Avalanche-photodiode frequency response,” J. Appl. Phys., vol. 38, no. 9, p. 3705–3714, 1967.
[18] M. P. a. J. E. Bowers, “40 GHz Si/Ge Uni-Traveling Carrier Waveguide Photodiode,” JOURNAL OF LIGHTWAVE TECHNOLOGY, VOL. 32, NO. 20, pp. 3502-3508, 15 Oct. 2014.