臺灣博碩士論文加值系統

為了發展高速光電元件，我們在藍寶石基板（sapphire, Al2O3）上先以有機金屬氣相磊晶(MOVPE)成長一層氮化鎵減少晶格不匹配，再利用電漿輔助分子束磊晶(PA-MBE)成長AlxGa1-xN/GaN異質接面III-V族半導體，藉由改變不同的鋁含量來探討樣品特性。此系列樣品我們改變鋁的等效壓力以控制樣品的鋁含量，接著利用X-ray繞射、掃描式電子顯微鏡(SEM)、原子力顯微鏡(AFM)、低溫霍爾量測以及Shubnikov-de Hass(SdH)量測來探討樣品本身的特性。
藉由X-ray的量測可得知鋁含量x分別為1.76%、2.3%、14.33%、22.03%、37.26%，五塊樣品(004)面AlGaN的Rocking Curve半高寬都只有300 (arcsec)左右可知樣品品質很好，由SEM與AFM的量測可知樣品的表面甚為平整，表面粗糙度最大的樣品僅2.0nm， 可確定樣品是以二維的型式成長，由低溫霍爾的量測，可以發現A、B、C、D樣品低溫區因缺陷所引發的庫倫散射很小，且此系列樣品的載子移動率都很高，最高的載子移動率有19593 cm2/Vs 為樣品A於8K所量到，由SdH的量測可清楚觀察到C、D兩塊樣品的震盪圖形可知量子井裡的二維電子氣是被侷限的。

In order to develop high speed photo-electronic device, first, we grew one layer of GaN by MOPVE to decline lattice mismatch. Then we used PA-MBE to grow AlxGa1-xN/GaN heterostructure III-V semiconductor. Via changing the content of aluminum, we can confer the characteristic of these samples. In these samples, we controlled the content of aluminum by changing the vapor of aluminum. And then we used X-ray diffraction, SEM, AFM, low temperature Hall measurement and SdH to study the characteristic of these samples.
Throughout X-ray diffraction, the aluminum content x are 1.76%, 2.3%, 14.33%, 22.03% and 37.26%. Due to (004) AlGaN Rocking Curve F.W.H.M. are only 300 arcsec, the quality of the five samples are extraordinary. In addition, SEM and AFM measurement indicate that this series samples’ interface are very smooth, and the roughest sample is only 2nm. It can make sure that samples were grown in mode of two-dimensional (2D). With low temperature Hall measurement, we can find out the Coulomb scattering which is from the defect are very small in the sample A, B, C, D. And the mobility of this series samples are very high, the highest mobility is sample A at 8K which is 19593 cm2/Vs. We can observe the oscillation of the sample C, D obviously in SdH measurement indicate that the 2DEG is confined in the potential well.

第一章 簡介 1
1-1 前言 1
1-2 半導體異質結構特性與二維電子氣 3
第二章 實驗儀器及其原理 7
2-1 X-ray繞射分析儀 7
2-2 掃描式電子顯微鏡 10
2-3 原子力顯微鏡 12
2-4 霍爾量測 15
2-5 Shubnikov-de Hass效應 20
第三章 低溫霍爾實驗 22
3-1 儀器櫃儀器 22
3-2 真空管路 24
3-3 杜瓦瓶 25
3-4 Insert 27
3-5 低溫霍爾實驗步驟 28
3-5-1 樣品製備 28
3-5-2 事前準備工作 29
3-5-3 淨化杜瓦瓶 32
3-5-4 傳輸液氦 35
3-5-5 樣品量測 37
第四章 實驗數據 40
4-1 樣品成長 40
4-2 X-ray數據 42
4-3掃描式電子顯微鏡與原子力顯微鏡數據分析 50
4-4 低溫霍爾量測數據 55
4-5 SdH量測結果分析 63
4-6 能帶分析 70
第五章 結論 73
參考文獻 75

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