研究藉由氧化鋁為閘極絕緣層來改善成長於矽基板上之氧化鋁鎵/氮化鎵高電子遷移率電晶體之線性度

Abstract

近年來，氮化鎵高電子移動率電晶體具有優越的特性使其在高功率，高溫，高崩潰偏壓以及高頻應用有很大的潛力。然而在高功率無線通訊遇到關鍵性難題，就是以複雜調變技術來達成高速率傳輸的目的時，此調變技術會導致動態訊號的產生，進而造成訊號失真，因此在射頻功率放大器中，元件線性度成為無線通訊系統中一項非常重要的參數。在本研究中，金氧半氮化鎵高電子移動率電晶體與一般傳統的蕭基閘極氮化鎵高電子移動率電晶體相較，擁有較好的元件線性度特性與較高的通道飽和電流。本研究成功製作出1.5微米閘極線寬的三氧化二鋁金氧半氮化鎵高電子移動率電晶體，並且將其電性分析與一般傳統的蕭基閘極氮化鎵高電子移動率電晶體相比，證實元件在線性度上有顯著的改善。本論文研究顯示，三氧化二鋁金氧半氮化鎵高電子移動率電晶體能有效的增進元件之線性度，有效地應用在無線通訊系統中的射頻功率放大器。

Superior properties of AlGaN/GaN HEMTs are promising contenders for high-power, high-temperature, high-breakdown, and high-frequency applications and have attracted much attention recently. However, one of the key issues for using AlGaN/GaN HEMTs for high-power radio-frequency (RF) applications is the quality of the transiting signals. For the modern wireless communication, here are many users, and the neighboring frequencies are usually located closely to each other. Hence, it is important to suppress the signal distortions for the device used in the communication system could not induce signal distortions. A among all intermodulation distortions, third-order intermodulation distortion (IM3) usually cannot be filtered out by the filter; therefore, IM3 dominates the linearity performance of the device and is the most important linearity criteria for wireless communication system. In this study, it’s found that MOS-HEMT exhibits better linearity and higher channel saturation current compared to the HEMTs with Schottky-gate. In this paper, we present the linearity characteristics of the Al2O3 AlGaN/GaN MOS-HEMTs on Si substrates with gate length 1.5μm, and compare it with the regular AlGaN/GaN HEMTs devices for device linearity improvement in this study.