铁电栅材料GaN基场效应晶体管的特性

Electrical Characteristic of GaN-Based Field-Effect Transistor with Ferroelectric Gate

针对铁电薄膜/GaN基FET结构,利用数值方法研究了铁电栅材料自发极化强度PS变化对GaN基表面电子浓度nS和场效应晶体管转移特性Id-Vg的影响,给出了典型PS和εr值下跨导gm与Vg的关系。结果表明:零栅压下,nS在随PS(0～±59μC/cm2)变化时有4～6个数量级的提高或降低;当Vg=0.65V、PS为-26～26μC/cm2时,nS提高约4个数量级;负栅压下,nS因受引起电子耗尽的PS的影响而降低6～7个数量级,而PS未对Id-Vg产生明显影响,跨导gm在1V左右的栅偏压下达到最大值。这些结果对利用铁电极化和退极化可能改善新型器件性能的研究具有重要意义。

The GaN-based field-effect transistor with the ferroelectric gate （FeFET） was investigated using a numerical analysis. The influence of the spontaneous polarization Ps on the carrier density ns at the surface of GaN base and the transfer characteristic Ia-Vg of FeFET were researched, and the relationship between transconductance gm and gate voltage V, was presented at the typical spontaneous polarization Ps and dielectric constant εT of ferroeleetric materials. The results show that without any gate voltage, ns increases or decreases by 4 - 6 orders of the magnitude while Ps varies from 0 to ±59μC/cm2 ; when Vg = 0.65 V and Ps is between - 26μC/cm2 and 26μC/cm2, ns increases by about 4 orders; ns decreases by 6 - 7 orders because of Ps under the negative gate voltage. Unfortunately, Ps cannot obviously impact on Id-Vg, and gm reaches the maximum value at the gate bias of about 1 V. These results are significance to possibly improve the performance of the new device using the ferroelectric polarization and depolarization.