Photodetector
Design of a pin photodetector
Create a high efficiency p-in photodetector capable of detecting a 5 Gb/s optical signal from a 50 pm diameter optical Mae. It will be utilised at a room temperature with a 500 input impedance.
For your design, you may assume the following:
You the maximum p- and retype doping densities are Nix 3.0° cm-1 and Mix 1×10. cm The diode is built on a severely doped silicon substrate.
The electron and hole minority carder lifetimes are c.=cv= 25 m,. the electron and hole mobilities are pa = 1000 cm1V-Is’and pa= 100 cm1V-4the carrier saturation velocity is via = 10i ark the p-contact resistivity is p<= 3))10-112cm1 but n-contact resistivity can be f.cted) the relative permittivity of the semiconductor is e./G=12 At the :4…el.& the ..<onauctors*.,,nion coefficient is o.= lo•cm, diode is anti-reflection coated .
a) Show that the absorption efficiency is greater than 80%.
b) Determine the value of the matching resistor required.
c) Demonstrate that Me RC time constant and carrier transit time are both 30gcor shorter. 0. di Draw the diode structure and describe the ph detector dimensions, as well as the thicknesses and doping of all semiconductor Myers .
