REFLECTION AND TRANSMISSION SECONDARY EMISSION FROM SILICON

Reflection and transmission secondary emission ratios have been measured for a thin Si sample with one surface activated to a state of negative electron affinity. Reflection-mode gains of 950 were observed at 20-keV primary energy. The highest transmission secondary emission ratio was 725 at 20-keV primary energy. The high secondary emission gains result from the effective negative electron affinity at the surface of the sample together with a long escape depth for internal secondaries.