Microwave AlGaN/GaN HFETs
Microwave AlGaN/GaN HFETs
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DOI：
10.1109/mmw.2005.1417998
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发表时间：
2005-04
影响因子：
3.6
通讯作者：
R. J. Trew;G. Bilbro;W. Kuang;Y. Liu;H. Yin
中科院分区：
文献类型：
--
作者：
R. J. Trew;G. Bilbro;W. Kuang;Y. Liu;H. Yin
本文介绍了微波 AlGaN/GaN 异质结构场效应晶体管的工作物理原理、性能潜力和器件开发现状。 AlGaN/GaN HFET 显示出在提高射频性能的微波放大器应用中的应用潜力。开发进展迅速，原型设备已证明射频输出功率密度高达 30 W/mm。对于单芯片操作来说，微波放大器的输出功率正在迅速接近 100W，并且这些器件可能很快就会在蜂窝基站发射器应用中找到应用。用于 X 波段雷达的设备正在开发中，射频性能正在迅速提高。 HFET 器件会经历多种可能限制性能的物理效应。这些效应由射频周期的高电流和高电压部分引入的非线性组成。高电流现象涉及导电沟道在高于临界电流密度的情况下运行，从而引发空间电荷效应。源电阻的大小由沟道电流调制，并且产生高源电阻。高电压效应包括栅电极的反向泄漏和随后的半导体表面上的电荷俘获效应，以及导电沟道中的射频击穿。这些效应会产生过早饱和效应。此外，在某些条件下，器件的高电压操作可以启动 IMPATT 操作模式。当这种情况发生时，通道电流增加并且射频增益增加。这种现象增强了设备的射频输出功率。物理限制效应可以通过适当的设计来控制，并且这些器件在实际应用中的使用前景非常好。
This article presents the operating physics, performance potential, and status of device development of microwave AlGaN/GaN heterostructure field-effect transistors. AlGaN/GaN HFETs show potential for use in improved RF performance microwave amplifier applications. Development progress has been rapid, and prototype devices have demonstrated RF output power density as high as 30 W/mm. Microwave amplifier output power is rapidly approaching 100 W for single-chip operation, and these devices may soon find application for cellular base station transmitter applications. Devices are being developed for use in X-band radars, and RF performance is rapidly improving. The HFET devices experience several physical effects that can limit performance. These effects consist of nonlinearities introduced during the high-current and high-voltage portions of the RF cycle. High-current phenomena involve the operation of the conducting channel above the critical current density for initiation of space-charge effects. The source resistance is modulated in magnitude by the channel current, and high source resistance results. High voltage effects include reverse leakage of the gate electrode and subsequent charge trapping effects on the semiconductor surface, and RF breakdown in the conducting channel. These effects can produce premature saturation effects. Also, under certain conditions, high voltage operation of the device can initiate an IMPATT mode of operation. When this occurs, the channel current increases and RF gain is increased. This phenomenon enhances the RF output power of the device. The physical limiting effects can be controlled with proper design, and the outlook for use of these devices in practical applications is excellent.