MOSFET gate oxide.scaling limits are examined with respect to time-dependent breakdown, defects, plasma process damage, mobility degradation, poly-gate depletion, inversion layer thickness, tunneling leakage, charge trapping, and gate delay. It is projected that the operating field will stay around 5MV/cm for reliability and optimum speed. Tunneling leakage prevents scaling below 2nm, which is sufficient for MOSFET scaling to 0.05 mu m.