以脈衝雷射沉積法成長低螺紋狀差排缺陷密度的高品質鍺薄膜並應用於pin型光偵測器製程

本實驗採用之前還未有人嘗試過的PLD系統磊晶鍺薄膜，並且利用於磊晶過程注入微量的氬氣，以及靶材的拋光此兩種方式，大幅的減少樣品表面生成的水滴狀顆粒，進而增加樣品表面的平坦度。在PLD系統中，沉積速率由雷射能量控制，因此可以使用相較於其他技術更低的溫度做磊晶。一般最普遍使用的CVD磊晶溫度至少需要600℃甚至更高溫，但高溫會產生S-K模式的生長，導致薄膜不平整。而本實驗中所使用的溫度只需500℃。此外，PLD磊晶過程中可以給予原子高動能，使其飛抵基板後能夠繼續移動至自由能較低的位置，形成良好的結晶性。經過磊晶後的樣品，再使用快速高溫熱退火的處理，藉此進一步的提高結晶性與降低TDD數量。實驗後所得到的高品質鍺薄膜即可當作樣品，並以本實驗所發展的微影技術完成光偵測器的封裝與後續的量測。

關鍵字

鍺薄膜；脈衝雷射沉積；螺紋狀差排缺陷密度；張力型應力；微影技術；光偵測器

並列摘要

In this experiment, we use pulsed laser deposition (PLD) system which has not been used to grow germanium (Ge) epitaxial thin film. And we reduce particulates of droplet like that appear on surface of samples by inject a trace of argon and use pol-ished targets. Thus increase the surface flatness of samples. In PLD system, the deposition rate is controlled by the laser energy, so we can use lower growth temperature than other techniques. The most usual technique for grow epitaxial layer is CVD system, but it needs at least 600℃. And the high temper-ature will occur S-K mode, resulting raise roughness of surface. In this experiment, we can grow at 500℃. In addition, in epitaxial process, laser can give high power to Ge atoms, so after Ge atoms arrive the substrates, they still have enough energy to move to the position of lower free energy. Then form a well quality. After finish the epitaxial layer, we will use rapid thermal annealing (RTA). It can not only improve the crystallinity and also reduce the threading dislocation density (TDD). As aforementioned result, we already have a high-quality Ge thin film. Then we can use it into lithography process which we develop in this experiment. After that, we can assemble it into a photodetector and do the subsequent measurement.

並列關鍵字

Ge thin film ； pulsed laser deposition (PLD) ； threading dislocation density (TDD) ； tensile strain ； lithography ； photodetector

參考文獻

[3]Donald A. Neamen, 2011, “Semiconductor Physics and Devices : Basic Principles, 4e”, McGraw-Hill Education

[2]A.Z. Al-Attili et al, 2015, “Spin-on doping of germanium-on-insulator wafers for monolithic light sources on silicon”, JJAP 54, 052101 (2015)

[4]D. Choi et al, 2008, “Low surface roughness and threading dislocation density Ge grow on Si (001)”, JCG 310(2008):4273-4279

[5]D. Chen et al, 2014, “Ultralow temperature ramping rate of LT to HT for the growth of high quality Ge epilayer on Si (100) by RPCVD”, ASS 299(2014):1-5

[6]D. Chen et al, 2014, “Ultrasmooth epitaxialGe grow on (001) Si utilizing a thin B-doped SiGe buffer layer”, APE 7(111301,2014)

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以脈衝雷射沉積法成長低螺紋狀差排缺陷密度的高品質鍺薄膜並應用於pin型光偵測器製程

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