本文關(guān)鍵詞：局域表面等離激元增強AlGaN基紫外探測器的研究　出處：《華中科技大學》2016年博士論文　論文類型：學位論文

  更多相關(guān)文章： 鋁鎵氮 歐姆接觸 納米球刻蝕技術(shù) 局域表面等離激元 日盲紫外探測器

【摘要】：紫外探測技術(shù)在軍用和民用領(lǐng)域均有著廣泛應用,第三代寬禁帶半導體材料AlGaN具有擊穿場強高、熱導率大、耐高溫、抗輻照等特點,由其制備的紫外光電探測器特別適合用于軍事、航天、工業(yè)等特殊環(huán)境。但是目前由于異質(zhì)外延生長的AlGaN材料中缺陷密度偏高,同時受限于AlGaN材料的摻雜和器件工藝,AlGaN基紫外探測器的響應度仍然低于預期效果,特別是日盲紫外波段探測器的性能仍有較大提升空間。針對AlGaN基日盲紫外探測器研制中面臨的關(guān)鍵問題,本文以經(jīng)過優(yōu)化MOCVD生長參數(shù)的AlGaN材料為基礎(chǔ),研究了高Al組份n型AlGaN歐姆接觸制備,結(jié)合金屬Al納米顆粒的局域表面等離激元提升AlGaN基金屬-半導體-金屬型日盲紫外探測器的性能,并嘗試將金屬A1納米結(jié)構(gòu)與其他AlGaN基日盲紫外探測器集成。本論文的研究工作具體為以下幾個方面：(1)探索高Al組分n型AlGaN材料的歐姆接觸制備。我們提出并驗證采用高溫氮氣退火可以修復高Al組分n型AlGaN材料中ICP刻蝕損傷,通過優(yōu)化金屬膜層、快速退火溫度和時間等工藝參數(shù),在ICP刻蝕并退火后的n型Al0.5Ga0.5N上制備了低阻歐姆接觸,借助X射線光電子能譜測試闡明高溫氮氣退火的修復損傷機制。(2)利用納米球刻蝕技術(shù)制備金屬納米結(jié)構(gòu),在不同基片上用旋涂法和漂移法實現(xiàn)大面積、低缺陷密度的單層PS球自組裝模板,結(jié)合PS球模板形貌工藝,以此為金屬蒸鍍掩膜,可以制作多種金屬納米結(jié)構(gòu),包括不同尺寸的金屬納米顆粒陣列、金屬納米網(wǎng)等。(3)借助FDTD Solutions軟件對納米球刻蝕技術(shù)制備的三角柱狀Al納米顆粒建模,并研究了其局域表面等離激元共振與和顆粒尺寸、介質(zhì)環(huán)境、入射光偏振性的關(guān)系,結(jié)合實驗結(jié)果驗證仿真模型,最終實現(xiàn)對Al納米顆粒陣列的局域表面等離激元共振特性進行靈活調(diào)控。(4)將納米球刻蝕技術(shù)制作的Al納米顆粒陣列集成在AlGaN基MSM型日盲探測器表面,極大提高探測器的響應度并有效降低器件的暗電流,器件暗電流在pA量級,最高峰值響應度在20V偏壓269nm處可達2.34A/W。研究了Al納米顆粒尺寸、電極結(jié)構(gòu)、工作偏壓對于探測器性能的影響。我們初步探討局域表面等離激元增強響應度機制。(5)提出具有納米網(wǎng)狀叉指電極的AlGaN基MSM型探測器的設(shè)計方案,對網(wǎng)狀電極結(jié)構(gòu)進行模擬優(yōu)化并開展器件制備工藝研究。我們嘗試性將A1納米顆粒陣列與AlGaN基PIN型日盲紫外探測器集成,尚未實現(xiàn)增強響應度,需要進一步改進金屬納米結(jié)構(gòu)設(shè)計。
[Abstract]:Ultraviolet detection technology has been widely used in military and civil fields. The third generation wide band gap semiconductor material AlGaN has the characteristics of high breakdown field, high thermal conductivity, high temperature resistance, radiation resistance and so on. The UV photodetectors prepared by them are especially suitable for military, aerospace, industrial and other special environments. But at present, the defect density of AlGaN materials grown by heteroepitaxial growth is on the high side. At the same time, the responsivity of AlGaN-based UV detectors is still lower than expected due to the doping of AlGaN materials and the fabrication of AlGaN-based UV detectors. Especially, the performance of solar blind UV detector still has great improvement space. The key problems in the development of AlGaN based solar blind ultraviolet detector are discussed. Based on the AlGaN material with optimized growth parameters of MOCVD, the ohmic contact preparation of n-type AlGaN with high Al content was studied in this paper. The properties of AlGaN based metal-semiconductor-metal solar blind UV detectors were improved by using local surface isoexcitators of Al nanoparticles. We also try to integrate metal A1 nanostructures with other AlGaN based diurnal blind UV detectors. The research work in this thesis is as follows: 1). The ohmic contact preparation of n-type AlGaN materials with high Al content was investigated. It was proposed and verified that high temperature nitrogen annealing can repair the ICP etching damage in n-type AlGaN materials with high Al content. Low resistivity ohmic contact was prepared on n-type ICP etched and annealed by optimizing the process parameters such as metal film, rapid annealing temperature and time. X-ray photoelectron spectroscopy (XPS) was used to explain the repair mechanism of high temperature nitrogen annealing. (2) Nanospheres etching technique was used to prepare metal nanostructures, and large area was realized by spin coating and drift method on different substrates. Low defect density single layer PS ball self-assembly template, combined with PS ball template morphology technology, can be used as metal evaporation mask to fabricate various metal nanostructures, including metal nanoparticles array of different sizes. FDTD Solutions software was used to model the triangular columnar Al nanoparticles prepared by nanospheres etching. The relationship between the local surface isoexciton resonance and particle size, dielectric environment and polarization of incident light is studied. The simulation model is verified by the experimental results. Finally, flexible regulation of the local surface isoexciton resonance characteristics of Al nanoparticles array is realized. The Al nanocrystalline array fabricated by nanospheres etching was integrated on the surface of AlGaN based MSM solar blind detector. The responsivity of the detector is greatly improved and the dark current of the device is reduced effectively. The dark current of the device is in the order of Pa. The maximum peak responsivity can reach 2.34 A / W at 269nm at 20V bias voltage. The size of Al nanoparticles and the electrode structure have been studied. The effect of operating bias on the performance of the detector. We discuss the mechanism of enhanced responsivity of local surface isopherons. The design scheme of AlGaN based MSM detector with nanometer mesh interDigital electrode is presented. The structure of the grid electrode was simulated and optimized, and the fabrication process of the device was studied. We tried to integrate the A1 nanoparticles array with the AlGaN based PIN solar blind UV detector, but the enhanced responsivity has not been achieved. The design of metal nanostructures needs to be further improved.
【學位授予單位】：華中科技大學
【學位級別】：博士
【學位授予年份】：2016
【分類號】：TN23

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