不同磊晶結構對氮化鋁鎵/氮化鎵高電子遷移率電晶體之發光特性研究

Light Emitting Characteristics of AlGaN/GaN HEMT with Different Epitaxial Layers

吳駿霖(Wu, Jun Lin)

指導教授 ： 黃智方

國立清華大學/電機資訊學院/電子工程研究所/碩士(2016年)

摘要

本實驗使用矽基板上磊晶氮化鋁鎵/氮化鎵試片製作新穎light-emitting HEMT，主要研究方向於發光的位置及分佈、不同磊晶層的發光波長調變及改善p-ohmic特性等。
本論文中使用相同製程三種試片: (A)在矽基板磊晶20 nm Al0.25Ga0.75N/GaN HEMT和表層50 nm的p型氮化鎵。(B)在矽基板磊晶20 nm Al0.32Ga0.68N/Al0.07Ga0.93N HEMT和表層50 nm的p型氮化鎵。(C)在矽基板磊晶10 nm Al0.25Ga0.75N/GaN HEMT和表層50 nm的p型氮化鎵。在三種試片的LE-HEMT結構中，最低的Ron,sp = 22 mΩ-cm2左右，最高的Id,max=334 mA/mm都在Sample A量測到。在電性方面藉由薄Ni/Au/ITO的p型氮化鎵接觸，讓Vturn-on從6 V改善至4.5 V。
在發光特性上，則是設計不同的光罩佈局來驗證發光圖形。另一方面則利用不同的磊晶結構來調變發光波長，量測到Sample A的波長為364.42 nm和Sample B的波長為352.27 nm。亦利用CCD影像軟體分析Sample A及Sample C的發光延伸長度，分別為38.4 μm和20.7 μm。

關鍵字

高電子遷移率電晶體 ； 發光二極體 ； 氮化鋁鎵/氮化鎵 ； 發光波長調變 ； 二維電子氣通道

並列摘要

In this thesis, a novel light-emitting HEMT on AlGaN/GaN epitaxial layers on Si substrate were fabricated. This study is focused on light-emitting positions, distribution and wave length modulation with different light emitting GaN epitaxial layers, current conducting layers and p-type ohmic contacts.
Devices on three kinds of epitaxial layers with the same fabrication process were investigated in this study: (A) a 20 nm Al0.25Ga0.75N/GaN HEMT on Si wafer with a 50 nm pGaN cap layer. (B) a 20 nm Al0.32Ga0.68N/Al0.07Ga0.93N HEMT on Si wafer with a 50 nm pGaN cap layer. (C) a 10 nm Al0.25Ga0.75N/GaN HEMT on Si wafer with a 50 nm pGaN cap layer. The observed lowest specific on-resistance among the LE-HEMTs structure is 22 mΩ-cm2 and the highest drain saturation current is 334 mA/mm on Sample A. For the on-state characteristics, the turn-on voltage (Vturn-on) can be improved from 6 V to 4.5 V by using Ni/Au/ITO as the p-type contacts.
For optical properties, we try to study light emitting patterns by different mask layout designs. The wavelength of the emitted light is 364.42 nm on Sample A and 352.27 nm on Sample B, indicating the modulation of wavelength by the epitaxial structures. The extracted characteristic length of the light distribution is 38.4 μm on Sample A and 20.7μm on Sample C, respectively, from images captured by a CCD camera.

並列關鍵字

HEMT ； LED ； AlGaN/GaN ； wavelength modulation ； 2DEG

參考文獻

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