为了缓解AlGaN/GaN high electron mobility transistors(HEMT)器件n型GaN缓冲层高的泄漏电流,本文提出了具有氟离子注入新型Al0.25Ga0.75N/GaN HEMT器件新结构.首先分析得出n型GaN缓冲层没有受主型陷阱时,器件输出特性为欧姆特性,这样就从理论和仿真方面解释了文献生长GaN缓冲层掺杂Fe,Mg等离子的原因.利用器件输出特性分别分析了栅边缘有和没有低掺杂漏极时,氟离子分别注入源区、栅极区域和漏区的情况,得出当氟离子注入源区时,形成的受主型陷阱能有效俘获源极发射的电子而减小GaN缓冲层的泄漏电流,击穿电压达到262V.通过减小GaN缓冲层体泄漏电流,提高器件击穿电压,设计具有一定输出功率新型AlGaN/GaN HEMT提供了科学依据.
In this paper,two-dimensional electron gas(2DEG) regions in AlGaN/GaN high electron mobility transistors(HEMTs) are realized by doping partial silicon into the AlGaN layer for the first time.A new electric field peak is introduced along the interface between the AlGaN and GaN buffer by the electric field modulation effect due to partial silicon positive charge.The high electric field near the gate for the complete silicon doping structure is effectively decreased,which makes the surface electric field uniform.The high electric field peak near the drain results from the potential difference between the surface and the depletion regions.Simulated breakdown curves that are the same as the test results are obtained for the first time by introducing an acceptor-like trap into the N-type GaN buffer.The proposed structure with partial silicon doping is better than the structure with complete silicon doping and conventional structures with the electric field plate near the drain.The breakdown voltage is improved from 296 V for the conventional structure to 400 V for the proposed one resulting from the uniform surface electric field.
为了优化传统AlGaN/GaN high electron mobility transistors结构表面电场分布,提高器件击穿电压和可靠性,本文利用不影响AlGaN/GaN异质结极化效应的Si3N4钝化层电荷分布,提出了一种Si3N4钝化层部分固定正电荷AlGaN/GaN high electron mobility transistors新结构.Si3N4钝化层中部分固定正电荷通过电场调制效应使表面电场分布中产生新的电场峰而趋于均匀.新电场峰使得新结构栅边缘和漏端高电场有效降低,器件击穿电压从传统结构的296V提高到新结构的650V,而且可靠性改善.通过Si3N4与AlGaN界面横、纵向电场分布,说明了产生表面电场峰的电场调制效应,为设计Si3N4层部分固定正电荷新结构提供了科学依据.Si3N4钝化层部分固定正电荷的补偿作用,使沟道二维电子气浓度增加,导通电阻减小,输出电流提高.
