Multiband optoelectronic device for colorimetric applications and related manufacturing process

Patent metadata

Field	Value
Publication number	US-9978802-B2
Application number	US-201615346578-A
Country	US
Kind code	B2
Filing date	Nov 8, 2016
Priority date	Jun 21, 2016
Publication date	May 22, 2018
Grant date	May 22, 2018

Abstract

An optoelectronic device for detecting radiation, comprising a semiconductor body including: a cathode region delimited by a front surface, having a first conductivity type and including a bottom layer; an anode region having a second conductivity type, which extends in the cathode region starting from the front surface and forms a surface junction with the cathode region; and a buried region having the second conductivity type, which extends within the cathode region and forms a buried junction with the bottom layer. The cathode region further includes a buffer layer, which is arranged underneath the anode region and overlies, in direct contact, the bottom layer. The buffer layer has a doping level higher than the doping level of the bottom layer.

First claim

The invention claimed is:

1. An optoelectronic device for detecting radiation, comprising:
a semiconductor body including:
a cathode region delimited by a front surface of the semiconductor body and having a first conductivity type, said cathode region having a lower layer;
an anode region having a second conductivity type, which extends in the cathode region starting from the front surface and forms a shallow junction with said cathode region; and
a first buried region having the second conductivity type, which extends within the cathode region and forms a first buried junction with said lower layer; wherein said cathode region further comprises a first buffer layer, which is arranged underneath the anode region and overlies, in direct contact, the lower layer, said first buffer layer having a doping level higher than a doping level of the lower layer;

a first trench, which traverses the front surface and extends in the cathode region, said first trench including a top portion, which traverses the first buffer layer, and a bottom portion, which extends within the lower layer;
a first dielectric coating region, which coats side walls of the top portion of the first trench; and
a first conductive region including a top portion, which extends within the top portion of the first trench, and is surrounded by the first dielectric coating region, and a respective bottom portion, which extends within the bottom portion of the first trench; wherein the first buried region surrounds laterally and underneath the bottom portion of the first conductive region, and directly contacts the bottom portion of the first conductive region.

2. The optoelectronic device according to claim 1 , wherein said shallow junction forms a Geiger-mode avalanche photodiode.

3. The optoelectronic device according to claim 1 , wherein said shallow junction is configured to generate, in response to radiation that impinges on the front surface, a first current proportional to a light intensity of a first spectral component of said radiation; and wherein said first buried junction is configured to generate a second current proportional to a light intensity of a second spectral component of said radiation.

4. An optoelectronic device for detecting radiation, comprising a semiconductor body including:
a cathode region delimited by a front surface of the semiconductor body and having a first conductivity type, said cathode region having a lower layer;
an anode region having a second conductivity type, which extends in the cathode region starting from the front surface and forms a shallow junction with said cathode region;
a first buried region having the second conductivity type, which extends within the cathode region and forms a first buried junction with said lower layer; wherein said cathode region further comprises a first buffer layer, which is arranged underneath the anode region and overlies, in direct contact, the lower layer, said first buffer layer having a doping level higher than a doping level of the lower layer; and
a second buried region having the second conductivity type, wherein said cathode region further comprises:
an upper layer, which is arranged over the first buffer layer;
a second buffer layer, which is arranged underneath the anode region and overlies, in direct contact, the upper layer, said second buffer layer having a doping level higher than a doping level of said upper layer.

5. The optoelectronic device according to claim 4 , wherein:
the first buried region is arranged between the lower layer and the first buffer layer, and directly contacts the lower layer and the first buffer layer; and
said second buried region is arranged between the upper layer and the second buffer layer, and directly contacts the upper layer and the second buffer layer; said optoelectronic device further comprising:
a first trench, which traverses the front surface and extends in the cathode region, said first trench traversing the first buffer layer and a portion of the first buried region;
a first conductive region, which extends within the first trench and contacts the first buffer layer and the first buried region;
a second trench, which traverses the front surface and extends in the cathode region, said second trench traversing the second buffer layer and a portion of the second buried region; and
a second conductive region, which extends within the second trench and contacts the second buffer layer and the second buried region.

6. The optoelectronic device according to claim 4 , further comprising:
a first trench, which traverses the front surface and extends in the cathode region, said first trench including a top portion, which traverses the first buffer layer, and a bottom portion, which extends within the lower layer;
a first dielectric coating region, which coats side walls of the top portion of the first trench;
a first conductive region including a top portion, which extends within the top portion of the first trench, and is surrounded by the first dielectric coating region, and a respective bottom portion, which extends within the bottom portion of the first trench, wherein the first buried region surrounds laterally and underneath the bottom portion of the first conductive region, and directly contacts the bottom portion of the first conductive region;
a second trench, which traverses the front surface and extends in the cathode region, said second trench including a top portion, which traverses the second buffer layer, and a bottom portion, which extends within the upper layer;
a second dielectric coating region, which coats side walls of the top portion of the second trench; and
a second conductive region including a respective top portion, which extends within the top portion of the second trench and is surrounded by the second dielectric coating region, and a respective bottom portion, which extends within the bottom portion of the second trench;
and wherein the second buried region surrounds laterally and underneath the bottom portion of the second conductive region, and directly contacts the bottom portion of the second conductive region.

7. An array comprising a plurality of optoelectronic devices for detecting radiation, each optoelectronic device including:
a cathode region formed in a semiconductor body, the cathode region being delimited by a front surface of the semiconductor body, and having a first conductivity type, said cathode region having a lower layer;
an anode region having a second conductivity type, which extends in the cathode region starting from the front surface and forms a shallow junction with said cathode region;
a first buried region having the second conductivity type, which extends within the cathode region and forms a first buried junction with said lower layer; wherein said cathode region further comprises a first buffer layer, which is arranged underneath the anode region and overlies, in direct contact, the lower layer, said first buffer layer having a doping level higher than a doping level of the lower layer;
a first trench, which traverses the front surface and extends in the cathode region, said first trench including a top portion, which traverses the first buffer layer, and a bottom portion, which extends within the lower layer;
a first dielectric coating region, which coats side walls of the top portion of the first trench; and
a first conductive region including a top portion, which extends within the top portion of the first trench, and is surrounded by the first dielectric coating region, and a respective bottom portion, which extends within the bottom portion of the first trench; wherein the first buried region surrounds laterally and underneath the bottom portion of the first conductive region, and directly contacts

Assignees

• St Microelectronics Srl

Inventors

• Mazzillo Massimo Cataldo
• Cinnera Martino Valeria

Classifications

• G01N21/251

  Colorimeters; Construction thereof · CPC title

• H01L27/14689

  Electricity · mapped topic

• H01L31/107

  Electricity · mapped topic

• H01L27/14645 Primary

  Electricity · mapped topic

• H01L27/14607

  Electricity · mapped topic