GaN HFET沟道中的电子态转换和沟道右势垒剪裁

Electron state transformation in GaN HFET channel and tailoring of right barrier in channel

在分析A lGaN/GaN沟道阱中电子迁移率、截止频率fT和噪声性能随电子气密度变化的基础上,研究了沟道电子态随电子密度的变化。发现在高电子密度下电子会向量子限制较弱的退局域态转移。同时还经由热电子隧穿而跃迁到表面态。在低电子密度下,沟道阱产生畸变而蜕化为三维态。运用这一电子态转换模型解释了输运噪声特性随电子气密度的变化。最后指出剪裁沟道右势垒可以弱化高、低电子气密度下输运和噪声性能的衰退。

From analyzing the dependency of GaN/GaN channel well, the electron states in electron mobility and fT upon electron concentration in Alchannel as a function of electron concentration is investigated. It is found that the electrons may be transferred into delocalized states with high energy and transited to surface states through hot electron tunneling under high electron concentration. At low electron concen- tration the channel well is deformed and so the two dimensional states are transformed into three dimensional states. Appling this state transform model the transport behavior of electrons in channel well as a function of electron concentration is explained satisfactorily. At last it is shown that the declining of transport and noise performance under high and low electron concentration may be weakened through the right barrier tailoring.