鍺錫金氧半發光元件與無接面環繞式閘極電晶體

GeSn Metal-insulator-semiconductor Light-emitting Devices and GeSn Junctionless Gate-all-around pFETs

張志強(Chih-Chiang Chang)

指導教授 ： 劉致為

國立臺灣大學/電機資訊學院/光電工程學研究所/碩士(2017年)

https://doi.org/10.6342/NTU201702114

摘要

本篇論文著重在新穎锗錫材料的磊晶技術、材料分析、磊晶品質檢測與光電元件和電晶體之設計、製備、量測以及特性分析。
鍺材料如今已漸漸應用於光電領域之中，相較於矽材料，鍺擁有較小的能隙，然而其間接能矽的特性卻限制了發光效率。利用鍺錫材料的特性能夠使其擁有直接能矽的特性，應用於光電元件之中能更進一步提升其效能。本論文中，製備了鍺錫材料的金氧半穿隧二極體，在電致發光量測中隨著不同錫含量而有不同的訊號，同時也能作為磊晶材料品質的檢測方法。
　　而隨著摩爾定律，半導體工業中藉著微縮電晶體尺寸來持續提高電晶體效能，然而，若要使傳統的矽金氧半場效電晶體技術突破物理極限，必須使用高遷移率的材料來取代矽以增加驅動電流，此外，電晶體也勢必需要從平面結構轉為三維結構來提高閘極控制能力和改善短通道效應。本論文中，利用化學氣相沉積進行硼/磷摻雜並成長高品質之鍺錫磊晶層，同時研究擁有高準確度的接觸電阻量測模和樣品製備。最終我們利用高摻雜濃度約3.5x1020 cm-3和1.2x1020 cm-3 之p型和n型鍺錫磊晶樣品進行接觸電阻率量測，其接觸電阻分別可達2.6x10-8 Ω-cm2 and 1.1x10-6 Ω-cm2。
　　最後，我們將高磊晶品質與高遷移率鍺錫通道與環繞式閘極無接面場效電晶體整合於絕緣層覆矽基板上，利用非等向性的蝕刻技術，有效地去除擁有高缺陷密度的鍺材料緩衝層，同時形成足夠細之鍺錫通道，此外，再加上環繞式閘極擁有較佳的閘極控制能力，因此可達到高電流開關比1.2x105以及次低臨界擺幅103，其導通電流可達510 μA/μm。

關鍵字

鍺錫 ； 金氧半發光二極體 ； 電致發光 ； 磊晶 ； 化學氣相沉積 ； 接觸電阻率 ； 環繞式閘極場效電晶體 ； 無接面

並列摘要

In this thesis, We focus on epitaxy technique, material analysis, and epitaxy quality on the promising materials GeSn. Besides, the optoelectronic MIS tunneling diodes and Junctionless GAA pFETs are fabricated.
Ge semiconductors have been widely used in optoelectronics integration due to its bandgap is twice less than Si. However, the luminous efficiency is still limited to its indirect bandgap. The indirect-to-direct transition of Ge can be achieved by Sn incorporation with epitaxy technique and thus further improve the luminous efficiency. In this work, GeSn MIS tunneling diodes are fabricated. The EL emission peak of high-quality epi-GeSn can be tuned by Sn content in the MIS tunneling diodes without the Ge cap.
The performance of MOSFETs can be enhanced by shrinking the critical dimension in semiconductor industry followed by the Moore’s law. However, to continually scale the device beyond the fundamental scaling limits, high mobility channel material which can increase the on state current and 3D structure with better gate control ability to reduce the short channel effect are necessary. The high quality in-situ B/P-doped epi-GeSn are grown by CVD. Hall concentration of 3.5x1020 cm-3 and 1.2x1020 cm-3 in B-doped and P-doped GeSn layer are both achieved. Contact resistivity of 2.6x10-8 Ω-cm2 and 1.1x10-6 Ω-cm2 for B-doped and P-doped GeSn can be obtained by RTLM model which has high accuracy.
Finally, junctionless gate-all-around pFETs are fabricated with high mobility GeSn channels. Ion/Ioff =1.2x105, Small SS=103 mV/dec, and Ion = 510 μA/μm at Vds = -1 V can be obtained because it has good gate control and the defect region under Ge buffer layer is removed by RIE during the channel formation process.

並列關鍵字

GeSn ； MIS tunneling diode ； Electroluminescence ； Epitaxy ； Chemical vapor deposition ； Contact resistivity ； Gate-all-around FETs ； Junctionless

參考文獻

[2] Wirths, Stephan, et al. "Lasing in direct-bandgap GeSn alloy grown on Si." Nature photonics 9.2 (2015): 88-92.

[3] G. E. Moore, “Cramming more components onto integrated circuits (Reprinted from Electronics, pg 114-117, April 19, 1965),” Proc. IEEE, vol. 86, no. 1, pp. 82-85, Jan, 1998.

[5] Mistry, Kaizad, et al. "A 45nm logic technology with high-k+ metal gate transistors, strained silicon, 9 Cu interconnect layers, 193nm dry patterning, and 100% Pb-free packaging." Electron Devices Meeting, 2007. IEDM 2007. IEEE International. IEEE, 2007.

[6] Auth, Chris, et al. "A 22nm high performance and low-power CMOS technology featuring fully-depleted tri-gate transistors, self-aligned contacts and high density MIM capacitors." VLSI technology (VLSIT), 2012 symposium on. IEEE, 2012.

[7] Coquand, Remi, et al. "Strain-induced performance enhancement of trigate and omega-gate nanowire FETs scaled down to 10-nm width." IEEE Transactions on Electron Devices 60.2 (2013): 727-732.