以濺鍍法沉積矽摻雜氮化鋁薄膜之可行性探討

Feasibility study of Si-doped AlN thin film using Helicon sputtering method

蔡明利(Ming-Li Tsai)

指導教授 ： 高慧玲

中原大學/工學院/電子工程研究所/碩士(2013年)

https://doi.org/10.6840/CYCU.2013.00117

摘要

近年來對寬能隙半導體材料之研究相當廣泛，其寬能隙特點適合應用於深紫外光領域，可作為深紫外光源或是光偵測器之材料。其中AlN之直接能隙高達6.2eV，擁有良好化學及熱穩定性、熱導性、抗輻射性等優點，使其適合應用於深紫外光光電元件、高功率元件等。為了使AlN能應用於元件中，必須將摻質有效地摻入薄膜中，改善薄膜導電性，達成理想p-n接面。目前針對摻雜AlN薄膜之研究仍相當有限，其關鍵問題在於基板與AlN間的晶格不匹配度，使AlN薄膜含有相當高的差排密度，進而限制摻雜效果，且大多採用高成本之基板與成長技術沉積AlN薄膜，造成應用上有所限制。
本研究採用迴旋濺鍍系統於sapphire基板上沉積c軸取向AlN單晶磊晶薄膜，並以Al-Si接合靶在沉積過程中摻雜AlN薄膜，經縱身濃度分佈量測證實，可藉由調整Si靶材直徑來控制摻雜濃度。對AlN施以1000℃之高溫退火處理，可降低其差排密度，但高溫熱破壞導致其表面結構損傷，影響其電性表現。以in situ方式沉積Al電極形成金屬接觸，其量得之接觸電阻率約10^1~10^5 Ω∙cm^2。

關鍵字

矽摻雜 ； 寬能隙 ； 氮化鋁 ； 濺鍍

並列摘要

Wide bandgap semiconductor materials were widely studied recently. The characteristics of wide bandgaps have made them suitable for fabricating deep ultraviolet light sources or photo-detectors. In numerous wide bandgap materials, aluminum nitride not only has wide bandgap (6.2eV) but also possess good chemical and thermal stability, thermal conductivity and radio-resistance, etc. Many advantages have made AlN be a good candidate for applications of DUV optoelectronic element and high power device. However, to realize the applicable AlN devices, appropriate impurities must be doped into AlN efficiently to improve conductivity and achieve good p-n junction. Currently, doped AlN films are short of research due to large lattice mismatch between AlN and substrates, which causes high threading dislocation density and limited doping efficiency. In addition, most research use high costly substrates and growth techniques, and hence result in high production cost and the restriction of commerce.
This study achieved the deposition of c-plane orientation AlN single crystal epitaxial film by using Helicon sputtering system. Silicon atoms were doped during the deposition by applying the use of Si attached Al target. According to the depth concentration profile results, Si doping concentration could be controlled via adjusting the area of Si on Al targets. Threading dislocation density in AlN film was reduced as a result of annealing treatment at 1000℃. However, the high temperature treatment caused thermal damage on AlN surface and affected the electrical property. After depositing Al metal on AlN in situ, the specific contact resistivity measured are equal to 10^1~10^5 Ω∙cm^2 approximately.

並列關鍵字

sputtering ； wide bandgap ； Si doped ； AlN

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