臺灣博碩士論文加值系統

本篇論文係以MBE技術及控制Ga、In及Al的流量，達到在InP上成長晶格匹配的InGaAs、InAlAs及InGaAlAs.在過量的As環境下，藉由控制放置Ga 的K-cell的溫度來調整Ga分子束的流量。在理想情況下，Ga的分子束流量與GaAs在GaAs基板上的長晶速率成正比，故我們可在不同的Ga溫度，量測RHEED oscillation frequency而得出Ga溫度與Ga流量的關係。當加入少量的In，可藉由長晶速率增加的比例算出Ga與In的分子束流量比。同理，在GaAs基板上成長AlAs或AlGaAs亦可得出Al的分子束流量。由以上的結果我們可調整In、Ga及Al的溫度來獲得InGaAs、InAlAs 及InGaAlAs的設計組成。經由X-ray繞射量測磊晶層晶格常數的誤差、及吸收光譜量測能隙的誤差，可作為各材料流量修正的參考，以提高晶格匹配準確度。
本篇論文實驗結果已初步建立本分子束磊晶實驗室的Ⅲ族材料Ga、In、Al的流量公式；在In的溫度833~836℃且長晶速率約在0.8□m/hr下，當Ga(1) 931℃、Al 1094℃時，可成長三元化合物In0.532Ga0.468As及In0.523Al0.477As並與InP基板晶格匹配；而當Ga(2) 912℃、Al 1059℃時，則可成長能隙值1eV的四元化合物In0.527Ga0.245Al0.228As並與InP基板晶格匹配。

This work is to control the fluxes of the Ga, In and Al sources in our MBE system to grow lattice-matched InGaAs, InAlAs and InGaAlAs epi-layers on InP substrates. With the As overpressure condition in the MBE system, we can control the temperature of Ga K-cell to modulate the flux of Ga. In ideal situation, the flux of Ga has a direct ratio with the GaAs growth rate on GaAs substrate, so we can find the Ga flux dependence on temperature by measuring the RHEED oscillation frequency. From the growth rate data of InGaAs on GaAs substrate at lower In composition, the In flux was obtained by comparing the growth rate ratio to the GaAs case. In the same way, we can also get the flux of Al by the growth of AlAs or AlGaAs on GaAs substrate. With the results of flux experiment, we can modulate the temperature of Ga, In and Al K-cells to compose InGaAs, InAlAs and InGaAlAs lattice-matched on InP substrates. The epi-layer quality was examined by X-ray diffraction and photo-absorption spectrum.
We have built the flux equations for the Ga, In and Al sources from the experiment data. With the In K-cell temperature at 833~836℃, Ga(1) at 931℃ and Al at 1094℃, we have grown ternary compound semiconductors of In0.532Ga0.468As and In0.523Al0.477As lattice-matched on InP substrates. When the In K-cell temperature at 833~836℃, Ga(2) at 912℃ and Al at 1059℃, a quaternary compound semiconductor of In0.527Ga0.245Al0.228As (Eg=1eV) lattice-matched on InP substrate was demonstrated.

第一章 簡介 1
1-1 前言 1
1-2 論文介紹 3
第二章 實驗原理介紹 4
2-1晶格匹配 4
2-2 RHEED理論 8
2-2-1 RHEED oscillation 10
2-3 X-ray繞射理論 13
2-4 吸收光譜量測 15
第三章 分子束磊晶系統介紹 18
3-1分子束磊晶實驗室 18
3-2真空及冷卻循環系統 19
3-3磊晶及量測系統 20
第四章 實驗步驟 21
4-1建立腔體真空環境 21
4-2基板表面清潔步驟 22
4-3基板溫度校正 24
4-4各材料流量的量測及校正 26
4-5成長三元化合物於InP基板 28
4-6成長四元化合物於InP基板 29
第五章 實驗結果與分析 30
5-1各材料流量與溫度關係 30
5-1-1 Ga流量量測結果 30
5-1-2 In流量量測結果 32
5-1-3 Al流量量測結果 35
5-1-4流量結果分析及校正 36
5-2 X-ray繞射圖與晶格匹配誤差 40
5-3 吸收光譜圖與能隙誤差 44
第六章 結論 47
參考文獻 48
附錄A InGaAlAs的能隙計算公式 50
附錄B 本實驗室磊晶材料的蒸氣壓與溫度關係 51

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