Cryogenic GaAs Integrated Circuits Using a Lightly Doped GaAs FET Structure

Several papers in recent years about GaAs MESFETs with low doping levels have shown that lowering the operating temperature of this device (to around 100K) [1,2], can improve the carrier transport properties inside the active layer. One observes a rise of electron mobility and saturation velocity which leads to an increase of transconductance and saturation drain-source current. Cooling GaAs integrated circuits provides a means of raising the charge/discharge current inside the parasitic capacitances; thus it may be possible to combine either the high switching speed of conventional MESFETs with a low power dissipation or a higher logic gate speed capability with no increase of consumption. This work presents the performance of cooled high speed logic gates, based on a special MESFET structure, designed for low temperature operation.