Low energy argon ion bombardment of silicon (111) may cause a variety of surface and subsurface damage. At moderately elevated sample temperatures of 600-800 K to prevent amorphization, the sputtering process leaves a step-and-terrace morphology, the (7×7) surface reconstruction may be partially disordered, and a distribution of ion-induced defects remain in a shallow, inhomogeneously strained, subsurface layer. We use a spot profile analysis of low energy electron diffraction data to measure a low-amplitude, continuous distribution of surface height, which occurs in addition to atomic-height steps and other shorter-range atomic disorder at the surface. For 230 eV argon ion fluences increasing in the range 10¹⁵-10¹⁷ cm^-2, we find a continuous surface height distribution whose amplitude (i.e. standard deviation of surface height) increases from hundredths of an Angstrom up to 0.15 Å, with an average lateral feature size of ≈ 40 Å. At an intermediate fluence of ≈ 2 × 10¹⁶ cm^-2, the amplitude of the surface deformation also increases from 0.05 to 0.15 Å as the ion flux is decreased from 6 × 10¹³ cm^-2s^-1 to 2 × 10¹³ cm^-2s^-1, suggesting that some increased surface annealing and defect diffusion during ion bombardment enhances the surface deformation observed. Embedded argon concentrations of up to ≈ 10¹⁵ cm^-2 are found. A simple theoretical estimate of the amplitude of surface height deformation due to strain around buried point defects is made. With a distribution of subsurface defects treated as small inclusions in an elastic continuum model for the solid, we find qualitative agreement with the fluence-dependent amplitude of surface-height variation determined experimentally.