US 12,356,740 B2
Transistor integration with stacked single-photon avalanche diode (SPAD) pixel arrays
Hong Wei Lee, San Jose, CA (US); Cristiano L. Niclass, San Jose, CA (US); Shingo Mandai, Mountain View, CA (US); and Xiaofeng Fan, San Jose, CA (US)
Assigned to Apple Inc., Cupertino, CA (US)
Filed by Apple Inc., Cupertino, CA (US)
Filed on Sep. 13, 2021, as Appl. No. 17/473,855.
Claims priority of provisional application 63/083,262, filed on Sep. 25, 2020.
Prior Publication US 2022/0102404 A1, Mar. 31, 2022
Int. Cl. H10F 39/00 (2025.01); H10F 30/225 (2025.01); H10F 39/18 (2025.01)
CPC H10F 39/8037 (2025.01) [H10F 30/225 (2025.01); H10F 39/803 (2025.01); H10F 39/809 (2025.01); H10F 39/807 (2025.01)] 19 Claims
OG exemplary drawing
 
1. A pixel of a pixel array, the pixel comprising:
isolation walls forming sides of the pixel and extending at least partially through a semiconductor substrate of the pixel array between a top surface of the pixel array and a light gathering surface of the pixel array opposite the top surface;
shallow trench isolation material extending from the top surface at least partially into the semiconductor substrate, wherein the shallow trench isolation material separates a first region of the pixel, a second region of the pixel, and a third region of the pixel;
a single-photon avalanche diode (SPAD) comprising:
a cathode layer adjacent to the top surface; and
an anode layer within the semiconductor substrate and adjoining a side of the cathode layer opposite the top surface; and
a control transistor adjacent to the top surface and electrically connected with the SPAD, wherein:
the control transistor is a first control transistor;
the pixel further comprises a second control transistor;
the first control transistor is a gating transistor formed within the third region;
the second control transistor is a quenching transistor electrically connected to the SPAD and formed within the first region; and
the anode layer and the cathode layer of the SPAD are formed at least partially in the second region.