Improvement of the high frequency performance of HEMTs by bufferless technology

By means of a 2D Monte Carlo simulation of 50-nm-gate lattice matched AlInAs/InGaAs HEMTs, we show the benefits of using bufferless technology in terms of improvement of the cutoff frequency and noise characteristics. We have found an increase of approximately a 15% in f/sub c/, f/sub t/ and f/sub max/. Moreover, though only a slight reduction of 0.2 dB in the minimum noise figure is obtained, the bufferless HEMT shows an important decrease of the noise resistance (almost 5 /spl Omega/) and a 2.3 dB increase of the associated gain at 94 GHz.