US 2001/0017786 A1 · Integrated optoelectronic device with an avalanche photodetector and method of making the same using commercial CMOS processes

Abstract

An integrated optoelectronic circuit chip for optical data communication systems includes a silicon substrate, at least one MOS field effect transistor (MOSFET) formed on a portion of the silicon substrate, and an avalanche photodetector operatively responsive to an incident optical signal and formed on another portion of the substrate. The avalanche photodetector includes a light absorbing region extending from a top surface of the silicon substrate to a depth h and doped to a first conductivity type. The light absorbing region is ionizable by the incident optical signal to form freed charge carriers in the light absorbing region. A light responsive region is formed in the light absorbing region and extends from the top surface of the silicon substrate to a depth of less than h. The light responsive region is doped to a second conductivity type of opposite polarity to the first conductivity type. The light absorbing region and the light responsive region form a P-N junction at the interface therebetween such that when the light absorbing and light responsive regions are appropriately reverse biased, the freed charge carriers in the light absorbing region are amplified by avalanche multiplication.

Claims17

Dependent claims

An integrated optoelectronic circuit for optical data communication systems, comprising:

a silicon substrate having a top surface;
an MOS field effect transistor (MOSFET) formed on a portion of said silicon substrate;
an avalanche photodetector operatively responsive to an incident optical signal and formed on another portion of said silicon substrate, comprising:
a light absorbing region extending from the top surface of said silicon substrate to a predetermined depth h and doped to a first conductivity type, so as to be operatively capable of ionization from the incident optical signal to form freed charge carriers in said light absorbing region;
a light responsive region formed in said light absorbing region and extending from the top surface of said silicon substrate to a predetermined depth of less than h, said light responsive region being doped to a second conductivity type of opposite polarity to said first conductivity type, said light absorbing region and said light responsive region forming a P-N junction at an interface defined between said light absorbing region and said light responsive region such that the freed charge carriers in said light absorbing region undergo avalanche multiplication when said light absorbing region and said light responsive region are sufficiently reverse biased.

2 more elements

A method of producing an integrated optoelectronic circuit, comprising the steps of:

(a) providing a silicon substrate;
(b) forming an MOS field effect transistor on one portion of the silicon substrate using a CMOS-compatible process;
and
(c) forming an avalanche photodetector on another portion of the silicon substrate using said CMOS-compatible process by:
(i) doping the another portion of the silicon substrate with a dopant of a first conductivity type so as to form a light absorbing region having a depth h1 and of said first conductivity type;
(ii) doping a portion of said light absorbing region with a dopant of a second conductivity type of opposite polarity to the first conductivity type to a depth h2 less than h1 so as to form a light responsive region having said depth h2 and of said second conductivity type, to thereby form a P-N junction at an interface defined between the light absorbing region and the light responsive region;
and
(iii) forming a guard ring circumferentially along an edge of the light responsive region for preventing premature breakdown of the photodetector when the light absorbing region and the light responsive region are reverse biased to thereby create a breakdown electric field.

5 more elements

Dependencies are inferred from the claim text.

Integrated optoelectronic device with an avalanche photodetector and method of making the same using commercial CMOS processes

Life of this patent

Integrated optoelectronic device with an avalanche photodetector and method of making the same using commercial CMOS processes

Life of this patent

Abstract

Claims17