Angular Dependence of InP High Electron Mobility Transistors for Cryogenic Low Noise Amplifiers under a magnetic field
This work addresses the angular dependence of DC properties in InP HEMT devices under the influence of applied static magnetic field at 2 K. When kept at an angle 90 degrees towards a magnetic field of 14 T, the maximum output drain current Ids was reduced drastically. A rotation sweep of the transistor revealed a strong angular and B field dependence on Ids. This was correlated with a reduction in dc transconductance and increase in on resistance of the transistor. The RF properties of the transistor were tested by measuring an 0.3 14 GHz InP HEMT MMIC low noise amplifier (LNA) at 2 K kept at an angle 90 degrees towards a magnetic field up to 10 T. The gain and noise temperature were strongly decreased and increased, respectively, already below 1 T. The results show that precise alignment of the cryogenic InP HEMT LNA is crucial in a magnetic field. Even a slight mis orientation of a few degrees leads to a strong degradation of the gain and noise temperature. ain and noise temperature.
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