Building on a previously presented compact gate capacitance (Cg–Vg ) model, a computationally efficient and accurate physically based compact model of gate substrateinjected tunneling current (Ig–Vg ) is provided for both ultrathin SiO2 and high-dielectric constant (high-.) gate stacks of equivalent oxide thickness (EOT) down to . 1 nm. Direct and Fowler–Nordheim tunneling from multiple discrete subbands in the strong inversion layer are addressed. Subband energies in the presence of wave function penetration into the gate dielectric, charge distributions among the subbands subject to Fermi–Dirac statistics, and the barrier potential are provided from the compact Cg–Vg model. A modified version of the conventional Wentzel–Kramer–Brillouin approximation allows for the effects of the abrupt material interfaces and nonparabolicities in complex
band structures of the individual dielectrics on the tunneling current. This compact model produces simulation results comparable to those obtained via computatio