鐵/碳摻雜緩衝層對氮化鋁鎵/氮化鎵高電子遷移率電晶體影響的研究

Investigation on the Effect of Iron/Carbon-Doped Buffer Layer for AlGaN/GaN HEMT

張博軒(Po-Hsuan Chang)

指導教授 ： 李冠慰

義守大學/智慧科技學院/電子工程學系/碩士(2022年)

摘要

本論文研究了摻雜碳和摻雜碳/鐵的氮化鎵緩衝層結構，了解缺陷如何影響氮化鋁鎵/氮化鎵高電子遷移率電晶體的特性。傳統上的功率元件，因為鐵摻雜有大的記憶效應，會使鐵離子向外擴散導致元件特性下降；相比之下，碳摻雜具有較小的記憶效應，因此問題比鐵小。本實驗在鐵摻雜緩衝層上方再加上一層碳摻雜緩衝層，目的是為了抑制鐵離子擴散。為了瞭解元件特性，除了直流量測外，也對缺陷的部分進行低頻雜訊、脈衝量測、變溫直流。實驗結果顯示，對於相同結構的元件，在低頻雜訊部分，單獨使用碳摻雜元件雜訊較低，表示單獨使用碳摻雜元件的缺陷密度較少，缺陷捕捉及釋放載子的情形較少。而在脈衝量測的部分，單獨使用碳摻雜氮化鎵緩衝層元件，在汲極靜態偏壓為6 V時，動態電阻比值為1.27倍，而碳/鐵摻雜氮化鎵緩衝層元件則為1.44倍。因此，單獨使用碳摻雜氮化鎵緩衝層有較低的缺陷捕獲電子機率，會有比較好的動態電阻的特性。本實驗單獨使用摻碳的元件會有較少的缺陷以及更好的可靠度。

關鍵字

緩衝層缺陷 ； 氮化鎵 ； 高電子遷移率電晶體

並列摘要

This thesis investigates the structure of the gallium nitride (GaN) with single carbon-doped (C-doped) buffer layer and composite carbon/iron-doped (C/Fe-doped) buffer layer and how defects affect the characteristic of AlGaN/GaN HEMTs. In traditional power devices, due to iron doping having a large memory effect, it will cause iron ions to diffuse outwards thus causing the power device characteristic to drop. Carbon doping in contrast has a smaller memory effect, thus the problem is smaller than iron. In this experiment, a C-doped buffer layer was added above the Fe-doped buffer layer to form a composite layer to suppress the diffusion of iron ions. In order to understand device characteristics, in addition to DC measurement, low-frequency noise, pulse measurement, and variable temperature DC measurement are also performed on the buffer layer defects of the devices.
The experiment results shows that for devices with the same structure, in the low-frequency noise section, the noise of the single C-doped devices is lower compared to composite C/Fe doped devices, which means that the defect density of the single C-doped device is less, thus there are fewer defects in capturing and releasing carriers. In the pulse measurement section, the single C-doped GaN buffer layer device is used alone. The single C-doped GaN buffer device exhibits a superior dynamic Ron (1.27 times) than that of the C/Fe-doped GaN buffer device dynamic Ron (1.44 times) at VDSQ = 6 V. Therefore, the use of the single C-doped GaN buffer layer has a lower probability of defect trapping electrons and better dynamic resistance characteristics. From this experiment, we can conclude that the device with single C-doped device will have fewer defects and better reliability compared to C/Fe composite device.

並列關鍵字

buffer trap ； gallium nitride (GaN) ； igh Electron Mobility Transistor(HEMT)

參考文獻

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