50奈米鍺量子點/矽鍺殼 N-型金氧半光電晶體之研製與分析

Fabrication and Characterization of 50 nm Ge-QD/SiGe Shell NMOS Phototransistor

蔣承庭(Chen-Tin Chiang)

指導教授 ： 李佩雯

國立交通大學/電機學院/電子工程系所/碩士(2019年)

摘要

本論文透過一體成型之鍺量子點技術，應用於金氧半場效電晶體之通道區製作成鍺量子點/二氧化矽/矽鍺殼層之異質結構。同時利用蝕刻機台的參數調變研究，更加優化複晶矽鍺奈米柱的形成。不僅取得適合的蝕刻率，也讓複晶矽鍺奈米柱的輪廓更加陡直，使其在經過選擇性氧化形成鍺量子點時的位置掌控更為熟稔。而鍺量子點與矽鍺殼層間3 ~ 4 nm的二氧化矽則是解決了矽/鍺界面的晶格不匹配同時也作為閘極介電層，並以單晶、品質高的鍺量子點及矽鍺殼層作為光吸收層。閘極金屬則是選用可透光之氧化銦錫作為電極，製作出可垂直入射並適用於850 nm ~ 1550 nm近紅外光的光電晶體。
本論文透過改變矽基板type，從N-type矽改成P-type矽製作出閘氧化層3.5 nm、鍺量子點大小為50 nm的光電晶體。當元件開啟狀態時，不僅光電流提升，以光功率約4.7 nW、3.92 W、87.3 nW，波長850 nm、1310 nm及1550 nm光垂直入射下，光響應度分別為4255.3 A/W、1.58 A/W及38.9 A/W。另外以相同小功率照射所得的光響應度更是較同結構（鍺量子點大小、閘氧化層厚度）下的PMOS元件高出約2.3 ~ 6倍，顯示元件對於近紅外光波段的光響應度相當出色。

關鍵字

鍺量子點 ； 光電晶體

並列摘要

In this thesis, we used the technology of Germanium quantum dots in a single process forming to fabricated a heterostructure of Ge Quantum Dots/SiO2/SiGe shell in the channel of a MOSFET. In order to optimize the forming of poly-SiGe pillar, we tune the etcher not only to get the adaptive etching rate and more vertical profile, but also to further control the distribution of Ge quantum dots. The 3-4 nm-thickness SiO2 between Ge QD and SiGe shell acts the gate oxide, solved the lattice mismatch at interface of Si-Ge. For normal incidence optimal transmission and applied to wavelength 850 nm to 1550 nm, we get the single-crystallize, high quality Ge QDs and SiGe shell for absorption layer and use ITO which is transparent as the gate electrode.
We change the type of silicon substrate from N-type to P-type to manufacture 50 nm QD-NMOS with 3.5 nm-thickness gate oxide. At on state, the photocurrent is more higher, in addition, under normal illumination of incident power about 4.7 nW, 3.92 W, 87.3 nW at wavelength of 850 nm, 1310 nm, and 1550 nm, we can get the photoresponsivity that is 4255.3 A/W, 1.58 A/W, and 38.9 A/W, respectively. In other hand, compared with the PMOS device with same condition in other structure parameters, size of Ge QDs and thickness of gate oxide, the photoresponsivity of NMOS is about 2.3 ~ 6 times higher than PMOS. Combine the measurement results above showing that the phototransistor has a great performance in the near-infrared ray regime.

並列關鍵字

Germanium Quantum Dots ； Phototransistor

參考文獻

[1] M. Bohr, "The evolution of scaling from the homogeneous era to the heterogeneous era," 2011 international electron devices meeting, 2011, pp. 1.1. 1-1.1. 6, IEEE.

[2] G. E. Moore, "Cramming more components onto integrated circuits. Electronics, 38 (8), April 1965," VLSI Technologies and Architectures, 2010.

[3] N. Srivastava and K. J. J. Banerjee, "Interconnect challenges for nanoscale electronic circuits," Jom, vol. 56, no. 10, pp. 30-31, 2004.

[4] https://case.ntu.edu.tw/blog/?p=22022

[5] X. Chen, Y. Huo, S. Cho, B.-G. Park, J. S. Harris, "Surface Treatment of Ge Grown Epitaxially on Si by Ex-Situ Annealing for Optical Computing by Ge Technology," IEIE Transactions on Smart Processing & Computing, vol. 3, no. 5, pp. 331-337, 2014.