氮化鎵上低溫濺鍍氮化鋁超薄薄膜異質接面結構之特性探討及研究

由於近年來在磊晶技術上有很大的進展，成功製作出品質良好的寬能隙三族氮化物，適合用來製作上述之高功率及短波長光電元件，此外也因其擁有較高的化學、機械及熱穩定性，使其在應用於惡劣環境下工作非常有利。在三族氮化物中特別是氮化鋁，因其具高熱穩定性、高導熱度、高表面聲波波速、寬直接能隙、高壓電性及強極化特性，使得氮化鋁非常適合用於製作表面聲波元件、紫外光光電元件、高頻及高功率元件。本研究之目的是在GaN/Sapphire基板上低溫成長AlN超薄薄膜其受到極化效應感應產生二維電子氣，使用低溫霍爾量測系統量測低溫載子濃度及載子遷移率。使用了X光繞射儀測量AlN的a軸以及c軸晶格長度，並使用倒置空間圖譜觀察AlN以及GaN薄膜之間應變，以及使用X光反射率量測 AlN薄膜厚度，並使用AFM量測AlN及GaN薄膜表面粗糙度。本論文使用Helicon迴旋濺鍍系統在GaN/Sapphire上沉積AlN超薄薄膜，並從低溫霍爾量測系統中發現，跟文獻報告指出於界面處感應形成二維電子氣並不相同，因此進一步利用X光繞射儀以及倒置空間圖譜量測發現所成長的AlN 薄膜a軸晶格長度並無受到GaN伸張應力的影響而有變化，可能成長的薄膜已超過其臨界厚度。因此期望未來朝向成長更薄薄膜之AlN/GaN異質接面結構做進一步探討及研究

關鍵字

迴旋濺鍍系統； X光繞射儀；倒置空間圖；低溫成長；二維電子氣；氮化鋁；氮化鎵

並列摘要

Ⅲ-nitride materials, especially AlN and GaN, uniquely present at the same time the excellent electric, optoelectronic and acoustic properties. They are attractive for optoelectronic and high power, high temperature device applications. The high drift carrier velocity, large conduction band discontinuity, and strong electrostatic field at the interface of the AlGaN/GaN heterostucture have also led to the study of high density two-dimensional electron gas (2DEG) formed at the interface under the influence of macroscopic polarization. In addition, these materials are also suited for high temperature piezoelectrics, pyroelectric sensors, and surface acoustic wave devices, due to strong lattice polarization effects. The aims of this thesis are to deposit ultra thin epitaxial AlN films on GaN/Sapphire substrates at low growth temperature, and to investigate the interface structure and the presence of large polarization filed in the AlN barrier layer which theoretically results in high values of the 2DEG sheet density. X-ray diffraction was employed in this thesis to measure the AlN a-axis and c-axis lattice constant, and the reciprocal lattice map was used to observe the strain of AlN film on GaN film. X-ray reflectivity and AFM were used to measure the AlN film thickness as well as the roughness of the surface and interface. In accordance with the experimental results, 2DEG of the AlN/GaN interface was not observed in the low temperature Hall measurement, which is not expected as in the reported literatures. It may be attributed to the strain relaxation in the interface of AlN and GaN films, according to the results of X-ray diffraction. Thinner film growth is suggested for future investigation on the growth mechanism of AlN/GaN heterostructure.

並列關鍵字

Helicon sputtering system ； X-ray diffraction ； reciprocal lattice map ； low temperature deposition ； 2DEG ； GaN ； AlN

參考文獻

38.張欣會, “III族氮化物之金屬-半導體-金屬紫外光感測器之特性研究”, 中原電子工程研究所碩士論文, 2007

44.吳俊德, “以迴旋濺鍍法製作AlN/GaN異質結構之二維電子氣特性研究”, 中原電子工程研究所碩士論文, 2004

3.T. Koyama, M. Sugawaral, Y. Uchinumal, J. F. Kaeding, R. Sharma, T. Onumal, S. Nakamura, and S. F. Chichibu, “ Strain-relaxation in NH3-source molecular beam epitaxy of AlN epilayers on GaN epitaxial templates”, Phys. Stat. sol. (a) 203, No. 7, pp.1603-1606, 2006

4.Y.A. Xi, K. X. Chen, F. Mont, J. K. Kim, C. Wetzel, E. F. Schuberta, W. Liu, X. Li, and J. A. Smart, “Very high quality AlN grown on (0001)Sapphire by metal-organic capor phase epitaxy”, APPLIED PHYSICS LETTERS 89, 103106, (2006).

5.K. S. Kao, C. C. Cheng and Y. C. Chen, "Synthesis of C-Axis Oriented Aluminum Nitride Films by Reactive RF Magnetron Sputtering for Surface Acoustic Wave", Jpn. J. Appl. Phys., 40, 4969 (2001).

國際替代計量

氮化鎵上低溫濺鍍氮化鋁超薄薄膜異質接面結構之特性探討及研究

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