Fabrication of vertically positioned silicon on insulator photo-activated modulator

In this paper we present the fabrication process and the experimental proof of principle of a vertical Silicon On Insulator Photo Activated Modulator (vertical SOI-PAM). In this device the information is electronic while the modulation command is photonic. Since photon illumination generates free charges and current, the information channel should be isolated by combination of metal and oxide layers in order to avoid cross-talk. However photo-generated charges are capable of closing the channel by inducing changes in the space charge layers on both sides of the oxide. The device is a vertical structure of n-type silicon resistor on oxide insulator above a p-type silicon substrate. The photonic modulation command is applied by top illumination of a specially etched V-groove in the p-type substrate in the vicinity of the resistor.