Enhancement-mode GaAs MOSFETs with an In0.3Ga0.7As channel, a mobility of over 5000 cm2/V•s, and transconductance of over 475 μS/μm

We present metal-gate high-kappa-dielectric enhancement-mode (e-mode) HI-V MOSFETs with the highest reported effective mobility and transconductance to date. The devices employ a GaGdO high-kappa (kappa = 20) gate stack, a Pt gate, and a delta-doped InGaAs/AlGaAs/GaAs heterostructure. Typical 1-mu m gate length device figures of merit are given as follows: saturation drive current, I-d,I-sat = 407 mu A/mu m; threshold voltage, V-t = +0.26 V; maximum extrinsic transconductance, g(m) = 477 mu S/mu m (the highest reported to date for a III-V MOSFET); gate leakage current, I-g = 30 pA; subthreshold swing, S = 102 mV/dec; on resistance, R-on = 1920 Omega center dot mu m; I-on/I-off ratio = 6.3 x 10(4); and output conductance,