Graded AlGaN Channel Transistors for Improved Current and Power Gain Linearity

We report on the small-signal high frequency characteristics of highly scaled graded AlGaN channel polarization-doped field-effect transistors (PolFETs) that show constant current gain cutoff frequency (fT) and maximum oscillation frequency (fmax) profiles as a function of current density or gate bias. The device design includes upward and downward Al composition grading to induce a distributed 3-...