Integrated photo detector, method of making the same

An integrated photo detector with enhanced electrostatic discharge damage (ESD) protection comprising:

• a Germanium photodiode comprising an intrinsic Germanium layer formed on a p-type Silicon base layer patterned within a Si-on-Insulator (SOI) substrate, the intrinsic Germanium layer comprising a first n++ doped region and the p-type Silicon base layer comprising a first p++ doped region;
• a Silicon photodiode comprising a Silicon region patterned within the SOI substrate to form a p-type Silicon portion joined with a n-type Silicon portion, the p-type Silicon portion comprising a second p++ doped region and the n-type Silicon portion comprising a second n++ doped region;
• a first metallic layer being pattered to include a first p-electrode coupled to the first p++ doped region, a second p-electrode coupled to the second p++ doped region, a first electrode connected to the first p-electrode by a portion of the first metallic layer with a reducing width and connected to the second p-electrode by a first trace line;
• a second metallic layer being pattered to include a first n-electrode coupled to the first n++ doped region, a second n-electrode coupled to the second n++ doped region, a second electrode connected to the first n-electrode by a portion of the second metallic layer with a reducing width and connected to the second n-electrode by a second trace line;
• wherein the Silicon photodiode is coupled with the Germanium photodiode electrically in parallel with a capacitance of no greater than a few femto Faradays and an enhanced ESD threshold of about ±100V.

A method for manufacturing an integrated photo detector with improved electrostatic discharge damage (ESD) protection, the method comprising:

• forming a first Silicon base block and a second Silicon base block on a substrate;
• forming a Germanium photodiode partially in the first Silicon base block, the Germanium photodiode being associated with a first p-electrode and a first n-electrode;
• forming a Silicon photodiode in the second Silicon bask block, the Silicon photodiode being associated with a second p-electrode and a second n-electrode, the second p-electrode and the second n-electrode serving as two terminals of a capacitance no larger than a few femto Faradays;
• forming a first electrode and a second electrode separately on the substrate;
• forming a first metallic layer on the substrate, the first metallic layer being patterned to have a first portion with a reducing width connecting the first electrode to the first p-electrode and a second portion with a first trace line connecting the first electrode to the second p-electrode;
• forming a second metallic layer on the substrate, the second metallic layer being patterned to have a third portion with a reducing width to connect the second electrode to the first n-electrode and a fourth portion with a second trace line to connect the second electrode to the second n-electrode.