Comparison of carrier velocity in 0.25 mu m gate-length conventional, pseudomorphic, and lattice-matched modulation-doped FETs at 300 K and 77 K

Abstract

In this paper, we report microwave characterization of 0.25pm gatelength MODFET's at 300 and 77K. We have exploited the microwave S-parameter measurements of MODFET'S from 0.045-20 GHz to extract their HF equivalent network parameters. The details of these measurement technique will be published eisewheref101. By exploiting this technique, we have determined the effective carrier saturation velocity(uuat) and the average velocity ( U a v ) at 300 and 77K for these submicron gate-length devices. Utilizing the theoretical results [ll] and estimated d u e of channel-to-drain separation based on the capacitance data, uuot were calculated to be ranging from 1.13~ 10' to 4 . 6 0~ 10' cm/sec, depending on the type of MOD-FET and operating temperatures. The corresponding value of U,, were from 0.82 x lo7 and 3.84 x io7 cm/sec.