Fabrication of a Si Photodiode for Position Sensitive Radiation Detection

We have fabricated a position sensitive radiation detector by creating radiation damage regions in a Si photodiode. Radiation damage was created in layers at a depth of several $\mu$ m by $^{7}$Li and $^{16}$O ion beams which had an energy between 2 and 4 MeV. Ions were focused and scanned using a nuclear microprobe facility. The ion beam induced charge (IBIC) signals created in diodes during irradiation were simultaneously measured to monitor the exact ion beam fluence and analyzed to estimate the amount of defects created. By controlling the ion microbeam scanning system, graduated and position dependent radiation damage was produced in different micro-patterns. Such structures may be used as a simple position sensitive radiation sensor.