Low noise Geiger-mode avalanche photodiode and manufacturing process

A sensing system, comprising:

• an array of photodiodes integrated in a semiconductor die, each of the photodiodes of the array of photodiodes including:
• a semiconductive structure;
• a front epitaxial layer on the semiconductive structure, the front epitaxial layer having a first conductivity type;
• and
• an anode region extending into the front epitaxial layer, the anode region having a second conductivity type that is different from the first conductivity type;
• a plurality of gettering regions in the semiconductive structure;
• a first dielectric layer on a semiconductor body, the first dielectric layer defining a recess that exposes the anode region;
• and
• a second dielectric layer on the semiconductor body and on the first dielectric layer, the second dielectric layer extending into the recess;
• a light source optically coupled to the array of photodiodes, the light source configured to illuminate the array of photodiodes;
• and
• microcontroller circuitry electrically coupled to the array of photodiodes, the microcontroller circuitry configured to receive an output signal of the array, a display coupled to the microcontroller circuitry and configured to display information associated with an output of the microcontroller circuitry, the microcontroller circuitry including an analog-to-digital converter and a microcontroller coupled between the analog-to-digital converter and the display.

A method, comprising:

• forming a semiconductor body by:
• forming a front epitaxial layer on a semiconductive structure, the front epitaxial layer having a first conductivity type;
• and
• forming an anode region extending into the front epitaxial layer, the anode region having a second conductivity type that is different from the first conductivity type;
• forming a plurality of gettering regions in the semiconductive structure;
• forming a first dielectric layer on the semiconductor body, the first dielectric layer defining a recess that exposes the anode region;
• forming a second dielectric layer on the semiconductor body and on the first dielectric layer, the second dielectric layer extending into the recess;
• and
• forming a polysilicon layer on the first dielectric layer and contacting the semiconductor body in the recess, the polysilicon layer having the second conductivity type.