A Partially Depleted Absorber Photodiode with Graded Doping Injection Regions

Abstract

A partially depleted absorber photodiode with graded absorption injection regions is reported. The 880-nm-thick In0.53Ga0.47As absorption region consists of a depletion layer and graded n- and p-type undepleted injection regions. Under backside illumination at 1.55-μm wavelength, an 8-μm-diameter photodiode exhibited an increase in bandwidth with increasing photocurrent. A saturation current bandwidth product of 990 mA · GHz and a responsivity of 0.67 A/W were achieved.