Electron-stimulated desorption (ESD) and temperature programmed desorption (TPD) studies were conducted on trimethylsilane dosed Si(100) surfaces. Experiments investigating the effects of electron-beam irradiation on TPD spectra and ESD kinetic energy distributions of hydrogen from trimethylsilane covered Si(100) surfaces are reported. Electron-beam irradiation strongly influences subsequent TPD spectra. Electron-beam induced dissociation of physisorbed particles on the surface is demonstrated. It is concluded that electron irradiation of trimethylsilane covered Si(100) selectively enhances or induces specific hydrogen adsorbed states when physisorbed species are present on the surface.