  Bare reverse biased silicon photodiodes were exposed to 3eV He+, Ne+, Ar+,
N2+, N+ and H2O+ ions. In all cases an increase of the reverse current through
the diode was observed. This effect and its dependence on the ionization energy
of the incident ions and on other factors are qualitatively explained in the
framework of Auger-type surface neutralization theory. Amplification of the
ion-induced charge was observed with an avalanche photodiode under high applied
bias. The observed effect can be considered as ion-induced internal potential
electron emission into the conduction band of silicon. To the best of our
knowledge, no experimental evidence of such effect was previously reported.
Possible applications are discussed.
