NARROW-CHANNEL GAINP INGAAS/GAAS MODFETS FOR HIGH-FREQUENCY AND POWERAPPLICATIONS/

We have developed a new concept of narrow (50-80 Angstrom) channel MOD FET's, It is shown theoretically and experimentally that only the grou nd energy level is populated in the narrow-channel device, A new techn ique to measure mobility at the highest energies of the two-dimensiona l electron gas (2-DEG) was introduced, With the help of this technique it is shown that, in wide wells, electrons in the excited energy leve ls have low mobility and consequently degrade device performance, It i s shown theoretically and experimentally that the narrow-channel devic e has a higher electron sheet density and mobility and consequently be tter performance than a conventional wide-channel MODFET, Excellent qu ality GaxIn1-xP/InyGa1-yAs/GaAs MODFET's with a pseudomorphic barrier and a pseudomorphic channel were grown by MBE and OMVPE, Higher than 3 .4 . 10(12) cm(-2) electron sheet densities for single-side-doped MODF ET's on GaAs substrate were measured, One-tenth micron gate length MOD FET's achieved f(T)'s over 100 GHz and f(max)'s over 180 GHz, These re sults are comparable to the previously reported results for GaInP MODF ET with graded barriers, however the device structure is much simpler.