Planar germanium photodiodes.

Planar passivated germanium photodiodes have been developed whose useful response at 22 degrees C extends from 0.6 microm to 1.85 microm at a nominal operating voltage of 20 V. Typical characteristics at 22 degrees C are diode capacitance, 100 pF/cm(2); rise and fall times, 10 nsec; leakage current, 2.5 mA/cm(2) ; D*(1.54 microm) approximately 2.5 x 10(10) cm/W/ radicalHz with a 3-dB frequency of ~45 MHz. Single and multiple element detectors ranging in size from 2 x 0.25-mm(2) elements with 50-microm spacing between elements to 3-cm(2) quadrant detectors have been made successfully for operation at temperatures from 77 K to room temperature.