液相氧化法應用在砷化銦鎵/砷化銦鋁變晶高電子移動率電晶體之元件隔離

Device Isolation of Liquid Phase Oxidation on InGaAs/InAlAs Metamorphic High-Electron-Mobility Transistor

陳泓偉(Houng-Wei Chen)

指導教授 ： 李冠慰

義守大學/電機資訊學院/電子工程學系/碩士(2014年)

https://doi.org/10.6343/ISU.2014.00360

摘要

本論文為使用液相氧化法氧化砷化銦鎵/砷化銦鋁作為元件之間的絕緣層。在傳統的濕式蝕刻元件隔離製程上，會存在由元件主動區外露之側邊和閘極金屬相連接產生的漏電流，進而影響元件的特性。
使用液相氧化法的優點在於製程上便宜和簡便，本論文是將元件主動區之間裸露的側邊使用液相氧化方式形成隔離層，這種方式可大大減少製程的步驟。實驗證實，利用液相氧化法於砷化銦鎵/砷化鋁鎵變晶型高電子移動率電晶體之元件隔離，可得到直流及高頻特性的提升：最大飽和電流可以到達260 mm/mA、最大轉導可到達320 mS/mm、次臨界擺幅為99.04 mV/dec比起濕式蝕刻作元件隔離法的最大飽和電流為180 mm/mA、最大轉導為270 mS/mm、次臨界擺幅106.34 mV/dec來的優異。而在高頻特性而言，液相氧化法作元件隔離之fT 和fmax 分別為20 GHz和31 GHz，而濕式蝕刻元件隔離之fT和fmax 分別為12 GHz和22 GHz。此隔離法可有效改善因閘極金屬與裸露側邊連接處所造成之漏電流。

關鍵字

液相氧化法 ； 隔離 ； 變晶高電子移動率電晶體

並列摘要

The study demonstrated liquid phase oxidation (LPO) on device isolation of InGaAs/InAlAs metamorphic high-electron-mobility transistor (MHEMT). The fabrication of conventional field effect transistors exist a gate leakage current due to the gate metal contact over the sidewall of the mesa. Compare with other systems, LPO has some advantages like simple process, low temperature, low cost, control easily, and does not need any photo energy or plasma source. Only put the wafer into the growth solution at 50 °C, and the oxide film can be grown uniformly.
For the wet etching isolation of MHEMT, the peak transconductance and the maximum gate voltage are 270 mS/mm and 0.5 V, respectively. The subthreshold swing is 106.34 mV/dec, and the microwave characteristics, the fT and fmax are 12 GHZ and 22 GHZ, respectively. For the LPO isolation of MHEMT, the peak transconductance and the maximum gate voltage are 320 mS/mm and 0.5 V, respectively. The subthreshold swing is 99.04 mV/dec, and the two-terminal reverse gate leakage current density can be improved two orders of magnitude. For the microwave characteristics, the fT and fmax are 20 GHz and 31 GHz, respectively.
Consequently, the LPO isolation on InGaAs/InAlAs MHEMT is better than the wet etching isolation on InGaAs/InAlAs MHEMT.

並列關鍵字

liquid phase oxidation (LPO) ； isolation ； metamorphic high-electron-mobility transistor (MHEMT)

參考文獻

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