Theory of life time measurements with the scanning electron microscope: steady state

A theoretical steady state analysis is given of the scanning electron microscope method of measuring bulk life time in diodes, where the plane of the junction is perpendicular to the surface. The current in the junction is obtained as a function of the beam power, the beam penetration into the semiconductor, the value of the surface recombination velocity, and the distance of the beam to the junction. Particular attention is paid to the injection level, and sufficient conditions are formulated for low and high injection, in terms of the beam current and voltage. A new method for measuring large surface recombination velocities is suggested.