Electron backscattering from thin silicon crystals

Very thin silicon crystals (600–7000 Å) were produced by a combined thinning technique starting from silicon wafers. The backscattering of 15–35-keV electrons from these crystals was measured. The reduced backscattering rate is proportional to the thickness of the specimen but is much higher than theoretically expected. Extrapolation to zero backscattering rate, however, leads to a thickness of 140 Å. Both of these facts lead to the conclusion that plural scattering predominates.