Electron-beam measurements of minority-carrier lifetime distributions in ion-beam-damaged silicon

An electron-beam technique for the determination of the minority-carrier lifetime distribution in semiconductors is described. Because of the short range of low-energy electrons, it is possible to profile the lifetime distribution in regions considerably less than 1 μ below the semiconductor surface with a depth resolution near the surface better than 0.1 μ. To demonstrate the method, the damage profile due to inert-gas ion implantation in silicon has been measured. The experimental results show that after room-temperature implantation without higher-temperature annealing, some defects have penetrated more than an additional 0.1 μ beyond their generation depth. A possible mechanism for this defect penetration, the diffusion of simple vacancies, is discussed.