用几何磁阻法分析低噪声MESFET的噪声性能

Analysis of Noise Characteristics in GaAs Low-Noise MESFET Using a Geometric Magnetoresistance Method

利用MESFET沟道的几何磁阻效应,测定了器件有源层内的迁移率剖面分布,与此同时得到源漏串联电阻。验证了它们与器件噪声性能的对应关系。进一步研究了材料质量对器件噪声性能的影响,从而提出一种简单的、非破坏性的方法。该法可在MESFET进行微波噪声性能测试之前,有效地鉴别器件质量的优劣。

The carrier mobility ia the active n-layer of the GaAs low-noise MESFET and the total resistance of source-to-gate and gate-to-drain Rs+Rd(including the contact resistance) are determined simultaneously. This experimental method is based on the semiconductor geometric megnetoresistance effect. The mobility profile on the interface between the active and the buffer layers directly affects GaAs MESFET microwave characteristics, so does its Rs+Rd.In order to research the correlation of GaAs material quality and the low-noise performance of the devices, simple nondestructive method is provided. This method can effectively evaluate the quality of MESFET before the microwave characteristics of devices are measured.