以單一熱氧化製程步驟量身設計的SiGe側壁結構可同時形成成對的Ge量子點

Simultaneous formation of paired Ge quantum dots by thermal oxidation of designer poly-SiGe spacer

陳翰毓(Han-Yu Chen)

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

本文以實驗室長期研究選擇性氧化矽鍺以形成鍺量子點的製程基礎，開發出兩種獨特的鍺耦合量子點奈米結構。在溫度800900oC溫度區間氧化過程之中，也觀察到鍺量子點或是鍺間隙原子可以顯著地催化氮化矽表面緻密化。
本文以『多晶矽奈米嶺』披覆多晶矽鍺/氮化矽覆蓋層立體結構，以單一熱氧化製程步驟，即可在奈米嶺的側壁角落，製作出類豌豆莢的雙排鍺量子點串。相當程度地簡化了量子點定位的製程技術難度。在800-900oC熱氧化『多晶矽奈米嶺』披覆多晶矽鍺/氮化矽覆蓋層立體結構時，我們實驗觀察到鍺原子會催化周遭的氮化矽緻密化、分解甚至氧化。藉由穿透式電子顯微鏡(TEM)、掃描穿隧式電子顯微鏡(STEM)、X射線能量散射光譜(EDX map)分析，深入探討此奈米結構可以定位量子點的機制後，本文更進一步實驗設計鍺耦合雙量子點崁入『氮化矽奈米嶺』之最佳化製程。我們成功地製作出直徑小於20nm之鍺雙量子點崁入氮化矽奈米嶺中，最重要的是，雙量子點之間最小間距為7.2nm。

關鍵字

鍺 ； 量子點 ； 氮化矽緻密化 ； 積體電路製程 ； 耦合量子點

並列摘要

In this thesis, we have developed two unique fabrication approaches for the simultaneous formation of paired Ge quantum dots (QDs) in terms of designer spacer nanostructures of poly-SiGe encapsulating either the poly-Si or Si3N4 nanoridges in a single oxidation step at temperature 800900 oC. Concurrent with the formation of paired Ge QDs at each sidewall edge of the poly-Si or Si3N4 nanoridges, we have also observed that Ge QDs or Ge interstitials significantly catalyze the surface densification of Si3N4 at 800-900 oC.
Thanks to the conformal deposition of poly-Si0.85Ge0.15 encapsulating lithographically-patterned poly-Si/Si3N4 nanoridges in combination with designer spacer (overlayer, spacer stripe, and spacer island) and selective oxidation of poly-Si0.85Ge0.15, paired Ge QDs with diameters ranging from 2050nm were produced in a self-organized manner and self-aligned with each other along each sidewall of the poly-Si nanoridge. The diameters of the Ge QDs have a strong dependence on the Ge content of the poly-SiGe spacer structures, and are adjustable by varying the SiGe thickness and through lithographic patterning. The separation of the paired Ge QDs across the ridge is essentially determined by the width of the patterned poly-Si nanoridge. Inter-QD spacing along the sidewall of the nano-ridge is a consequence of heterogeneous nucleation and Ostwald Ripening. For process simplicity, we have also successfully fabricated paired Ge QDs at each sidewall edges of the Si3N4 nano-ridges. Paired Ge QDs with a diameter of less than 20 nm is achieved and most importantly, the minimum inter-dots spacing is 7.2 nm.

並列關鍵字

Ge ； quantum dots ； silicon nitride densification ； coupled quantum dots

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