利用連接分子束磊晶系統的臨場掃描穿隧顯微鏡我們觀察到了砷化鎵2x4，4x6和只有0.9埃厚度氧化鋁長在砷化鎵的表面。
利用臨場掃描穿隧顯微鏡我們證實了平整的膜表面可以利用分子束磊晶技術得到，而且我們也觀察到一些有趣的砷化鎵表面結構，另一方面，利用穿隧電子能譜，我們也得知在砷化鎵表面不管其參雜的雜質是n型還是p型，表面的重構是什麼，都會得到不對稱的能譜，經由這些能譜我們就可以得到砷化鎵在不同參雜情況和表面重構情況下表面電子密度的分佈，更進一步，我們可以指出其表面電子捕捉能階在能帶內的能量，並且藉以解釋為什麼在以砷化鎵為基板的n型和p型金氧半場效電晶體上行為的不同。為了能夠了解高介電常數材料和砷化鎵的介面，我們利用原子層沉積技術成長了一個循環的氧化鋁在砷化鎵的表面上借以代表其界面，透過臨場掃描探針顯微鏡和穿隧電子能譜我們發現氧化鋁的能譜仍然像砷化鎵一樣是不對稱的，換句話說氧化鋁無法消除來自砷化鎵基版的影響，除此之外我們也發現氧化鋁也會在價帶和傳導帶附近引起電子捕捉能階。和利用分子束磊晶技術所成長的超薄氧化釓比較後可以發現氧化釓沒有不對稱的能譜，這也間接證實了氧化釓比氧化鋁更能夠鈍化砷化鎵表面。
綜合以上結果，我們建立了電子能階密度分佈模型，透過此模型將可解釋以砷化鎵為基版的場效電晶體之行為。

In this work, we have connected the SPM chamber to MBE system, and this in-situ SPM system has provided the result including GaAs(100)-(2x4) surface, GaAs(100)-(4x6) surface, and the surface of ALD-Al2O3 on GaAs.
The smooth surface of GaAs had been achieved through MBE technique, and the interesting surface structure had been observed. The STS spectra also show that the GaAs(100)-(2x4) and GaAs(100)-(4x6) surface have different distribution of DOS to induce “flat” spectra. Finally, we had revealed the morphology and STS of one cycle ALD-Al2O3 on n-type and p-type GaAs, and the spectra indicate that the ALD Al2O3 induces large DOS near conduction band and valence band, and it can’t erase the effect came from GaAs. According to above data, we build the model of distribution of DOS for GaAs and ALD-Al2O3/GaAs to explain the different performance between p and n type MOS. Finally, we compare the STS between ALD-Al2O3/GaAs and MBE- Gd2O3/GaAs, and the STS of later imply that Gd2O3 maybe can cancel the effect came from GaAs to induce ‘flat spectrum’.

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