WA-B5 high-electron mobility transistors with selectively doped GaAs/n-AlGaAs heterojunctions
WA-B5 high-electron mobility transistors with selectively doped GaAs/n-AlGaAs heterojunctions
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WA-B5 选择性掺杂 GaAs/n-AlGaAs 异质结高电子迁移率晶体管
DOI：
10.1109/t-ed.1980.20234
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发表时间：
1980
影响因子：
3.1
通讯作者：
M. Fukuta
中科院分区：
文献类型：
--
作者：
T. Mimura;S. Hiyamizu;H. Hashimoto;M. Fukuta
异质结结构中最有趣的现象之一是Dingle等人首先报道了分子束外延生长的调制掺杂GaAsA1，GaAl-As超晶格中的迁移率增强行为。在本文中，我们描述了一种具有超高速微波性能的新型场效应电阻器。该器件通过控制高迁移率电子的密度来工作，这些高迁移率电子聚集在靠近GaAs-AlXGal-As界面的GaAs侧。此后，我们将这种器件称为高电子迁移率晶体管(HEMT)。采用分子束外延技术生长了厚度为1.0 pm的HEMT外延层。它由非掺杂的GaAs缓冲层和在半绝缘的GaAs衬底上连续生长的非掺杂的n-Al，GaL-，As(x=0.32)覆盖。掺杂量为7×10‘/cm~3。高迁移率电子的密度可以通过电子累积层和栅电极之间的电容耦合由栅压来控制。我们同时制作了2 nm栅长的HEMT、霍尔桥和二极管，用于晶片中的C-V测量。电子密度n1=7.2×10~(-1)/crn~2，霍尔迁移率p~=6180 cmZ/V。S的新发现。用差动电容反馈轮廓仪测量了样品的电子密度峰值n=5×1017/cm~3。我们观察到栅极的漏极电流完全夹断，并且在相当高的漏极电压下漏极电流饱和。为了评估它的微波性能，我们在2-12 GHz的频率范围内测量了S参数。单位电流增益频率FT为8.2 GHz，比传统的2 PM栅长的GaAsMESFET高20%。当HEMT被冷却到77K时，我们观察到跨导急剧增加了2到4倍，这取决于器件的工作条件。这种跨导的增加部分是由于77K时电子迁移率的增加，测得77K时的霍尔迁移率为32500 cm~2/V S，高于已报道的调制掺杂超晶格的迁移率。
One of the most interesting phenomena in heterojunction structures is the mobility enhancement behavior first reported by Dingle et a1.I in MBE grown modulation-doped GaAsA1,Gal-,As superlattices. In this paper, we describe a novel field-effect ransistor with extremely high-speed microwave capabilities. The device is operated by controlling the density of high-mobility electrons accumulated at the GaAs side near a GaAs-AlXGal-,As interface. Hereafter, we call the device a high electron mobility transistor (HEMT). The epilayer of the HEMT, 1.0 pm thick, was grown by MBE. It consists of a nondoped GaAs buffer layer and Sidoped n-Al,Gal-,As (x = 0.32) covered by nondoped GaAs grown successively o n a semi-insulating GaAs substrate. The doping level is 7 X 10’ ‘/cm3. The density of the high-mobility electrons can be controlled by a gate voltage through a capacitance coupling between the electron accumulation layer and the gate electrode. We have simultaneously fabricated 2-,urn gate length HEMT’s, Hall bridges, and diodes for C-V measurement in the wafer. The electron density n, = 7.2 X lO1l/crn2 and Hall mobility p~ = 6 180 cmZ/V . s are observed. The sample has been measured with a differential capacitance feedback profiler, showing the peak value of the electron density n = 5 X 1017/cm3. We observed complete pinchoff of the drain current from the gate and drain-current saturation at reasonably high-drain voltages. To assess its microwave capabilities, we measured s parameters in the frequency range 2-12 GHz. The unity current gain frequency fT was 8.2 GHz which is 20 percent higher than that of a conventional 2-pm gate length GaAs MESFET. When the HEMT was cooled to 77 K, we observed a dramatic increase in transconductance by a factor as much as 2 t o 4, depending on the operation condition of the device. This increase in transconductance is partly due to the increase in the electron mobility at 77 K. The Hall mobility measured a t 77 K was 32500 cm2/V s, which is higher than what has thus far been reported in modulation-doped superlattices.