Effects of electron beam irradiation followed by thermal chlorine etching on InAs substrate

For the first time? the influence of an electron beam irradiation on InAs with native oxides was investigated. An irradiation modifies the chemical and physical properties of the surface oxides. The latent image can later be revealed by in situ exposure to Cl-2 gas at 190 degrees C. The etching rate by Cl-2 of the irradiated native oxides depends on the experimental conditions; it can be either increased or decreased. In consequence, differently irradiated zones of a sample surface later exposed to Cl-2 are more or less etched than the non irradiated areas. The effect depends not only on the dose, but also on the electron energy: an irradiation is more effective at low energy. A stationary beam exposure at 30 keV reveals the contribution of the backscattered electrons: their geometrical and energetic spreading and the effect of a gradual variation of the dose. This experiment is compared to the spatial distribution of the backscattered electrons obtained by means of a Monte-Carlo type calculation.