Charge exchange process for medium energy He ions backscattered from solid surfaces was studied using a high-resolution toroidal electrostatic analyzer(&Dgr;E/E=9×10−4).He ions backscattered from topmost atoms have a high fraction of nonqeuilibrium singly-ionized charge state and thus it generates a surface peak in the backscattering spectrum from an amorphous solid. The height and width of the surface peak provide the information about the electron capture and loss cross sections together with the ion-surface interaction region expanded from the top atomic plane toward the vacuum side. Dependence of the surface peak profile upon energy, exit-angle and materials of the surface is discussed in detail in the context of the ion-surface interactions. ©2000 American Institute of Physics.