Ga_(1-x)Al_xAs/GaAs异质结构二维电子气晶体管(TEGFET)

Current-Voltage Characteristics of Ga_(1-x)AI_x As/GaAs Heterostructure TEGFET

制备了耗尽型和增强型TEGFET,耗尽TEGFE单栅长1μm,其室温跨导g_m=90mS/mm;双栅栅长均为2μm。g_m=75mS/mm。双栅的结果优于本实验室相同结构与尺寸的离子注入型常规双栅MESFET与高掺杂沟道MIS结构肖特基势垒FET的实验结果。双栅耗尽型器件在77K下跨导增加到1.7倍。双栅增强型的TEGFET在室温0.6V栅偏压下,g_m=63mS/mm,在77K下增加到1.4倍。如器件中出现平行电导时,则器件性能退化,它不但使跨导降低,且随栅编压变化很大。文中讨论了这一现象。

Both normally-on and aormally-off TEGFET have been fabricated from the modulation-doped Ga1-xAlxAs/GaAs heterostructure grown by MBE. For normally-on transistors with single and dual gate, transcoaductances (gm) of 90mS/mm with 1μm gate length and of 75 mS/mm with 2 μgate length are achieved at 300K, respectively; the later is superior to that of ioa-implaated MESFET or MISSBFET with the same pattern and size using highly-doped channel. Upon cooling to 77 K, the transconiuctance of the dual gate D-TEGFET increases by a factor of 1.7. The gm of E-TEGFET with dual gate is 63mS/mm at the gate bias of V s= 0.6V and increases to 88 mS/mm at 77 K. It has also been observed that the characteristics of the device were degenerated and changed dramatically with gate bias when parallel conductance occured.