A silicon blue/UV selective stripe-shaped photodiode

A novel silicon photodiode for the selective blue/ultraviolet (UV) Light de tection is presented. A stripe-shaped anode geometry is used to improve the UV-responsivity of photodiodes fabricated in CMOS processes by minimizing the dead layer area. The selectivity is achieved using a shallow active reg ion, Limited by a high potential barrier at a depth of 450 nm. The measured devices, realized in standard 0.5 mu m CMOS technology, have maximum respo nsivity at lambda = 400 nm with a quantum efficiency of 53%. A ratio of the responsivities at 400 nm and 1 mu m of 100 is achieved. In comparison to s tructures with traditional anodes, our stripe-shaped photodiode shows an in crease of the UV responsivity by a factor 1.7, as predicted. The special an ode geometry also improves the photodiode shunt resistance. (C) 1999 Elsevi er Science S.A. All rights reserved.