Highly ionizing heavy charged particles generate significant charge as they pass through the thin thermally grown gate oxide of a MOSFET device. The amount of charge created by an alpha particle and proton is calculated and the yield of charqes which escape initial recombination is measured. The experimental results are shown to agree with a charge recombination model where an ionization track radius of 30-40 A is assumed. Finally, implications of the findings for single charged particle effects in submicron dimension devices are discussed.