以液相磊晶技術成長銻化銦磊晶層之特性研究

The Characteristics Study of InSb Epilayers Grown by LPE

林明忠(Ming-Chung Lin)

指導教授 ： 溫武義

中原大學/工學院/電子工程研究所/碩士(2004年)

https://doi.org/10.6840/cycu200400153

摘要

中文摘要

銻化銦(InSb)是在目前的Ⅲ-Ⅴ族化合物半導體中，同時擁有最小能隙(Eg = 0.17eV，300K)及最高電子遷移率(μn≦7700㎝2/V•s，300K)之材料。因此對於目前的應用範圍，非常適合拿來研製成高速元件、磁性感測器與紅外光檢測器等光電元件。
本論文乃利用液相磊晶的技術分別在銻化銦與砷化鎵(GaAs)基板上，成長同質與異質的銻化銦磊晶層。尤其是成長在砷化鎵異質磊晶，我們希望能尋求出最佳的成長參數，因為銻化銦與砷化鎵兩者間晶格不匹配度高達14.6％，但由於砷化鎵基板的價格遠低於銻化銦基板，因此非常值得我們深入研究。
本研究將以過冷卻成長法成長銻化銦的同質磊晶層；以階梯式冷卻法成長異質結構，其中我們特別針對Ⅲ/Ⅴ的重量比、成長溫度與成長時間等參數作進一步的探討。其後，將利用微分干涉顯微鏡、X光繞射分析儀、掃描式電子顯微鏡附加能量分散光譜儀與霍爾量測儀等設備，分析磊晶層之表面型態、晶格與側面結構與材料元素分析，以及最重要的電性分析。
對同質結構的磊晶實驗來說，我們已尋求到一組最佳化的成長參數（成長溫度：425℃、ΔT：10℃、降溫速率＜0.1℃/min、成長厚度約2~3μm）。磊晶層表面呈現連續且平滑的鏡面，其載子遷移速率於305K為5.93×104㎝2/V•s至115K則為8.27×104㎝2/V•s；載子濃度則由1.12×1015 /㎝3 (305K) 減少到4.25×1013 /㎝3 (115K)，而其載子類型為電子。在異質磊晶實驗方面，尚未尋求到一組能夠得到連續且平滑鏡面之成長參數。磊晶層表面呈現多晶結構且高低起伏不定，亦有多餘之銦元素與具有方向性之坑洞殘留於表面。而這些具有同向性之坑洞，來自於砷化鎵表面之砷元素在與成長溶液接觸時的回溶效應所造成。

關鍵字

液相磊晶 ； 砷化鎵 ； 銻化銦

並列摘要

Abstract

Among the Ⅲ-Ⅴ compound semiconductor, indium antimonide (InSb) has the lowest energy gap and the highest electron mobility. This material is very suitable to be used for the fabrication of the high-speed electronic devices, magnetic sensors, and the infrared detectors.
In this study, we use the technique of liquid phase epitaxy (LPE) to grow homo- and hetero-structure of InSb epilayers on the InSb and GaAs substrates, respectively, and expect to find an optimum condition for growing the highly mismatched InSb on the GaAs substrate with the lattice mismatch high to 14.6%. This kind of epitaxial growth is very difficult in itself. However GaAs wafers are 3~4 times cheaper in price, successful growth of InSb-on-GaAs can bring in great cost down in InSb-based devices. It’s worth while to carry out this research form the viewpoint of cost down.
For the epitaxial growth of homo-structure, we obtain an optimum growth parameters (the growth temperature: 425℃, the initial super-cooling ΔT: 10℃, the cooling ramp＜0.1℃/min, and the growth time: 20 min)。With the above conditions, a mirror-like smooth surface morphology was achieved. The mobility is 5.93×104 ㎝2/V•s at 300K and 8.24×104 ㎝2/V•s at 115K；the carrier density is reduced from 1.12×1015 /㎝3 at 305K to 4.25×1013 /㎝3 at 115K. The carrier type is electron. For the hetero-epitaxy, up to now only samples with rough morphology showing poly-crystal structure were obtained. There are unnecessary indium (In) and pits left on the surface. These pits are considered to due to the meltback of GaAs substrate in growth solution.

並列關鍵字

LPE ； InSb ； GaAs

參考文獻

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