	US 12,278,252 B2
	Photo-detecting apparatus with low dark current
Yen-Cheng Lu, Menlo Park, CA (US); Yun-Chung Na, San Jose, CA (US); Tsung-Ting Wu, Zhubei (TW); Shu-Lu Chen, Zhubei (TW); and Chih-Wei Yeh, Zhubei (TW)
Assigned to Artilux, Inc., Menlo Park, CA (US)
Filed by Artilux, Inc., Menlo Park, CA (US)
Filed on Aug. 27, 2021, as Appl. No. 17/458,819.
Application 17/458,819 is a continuation in part of application No. 17/005,288, filed on Aug. 27, 2020, granted, now 11,777,049.
Claims priority of provisional application 62/892,551, filed on Aug. 28, 2019.
Claims priority of provisional application 62/899,153, filed on Sep. 12, 2019.
Claims priority of provisional application 62/929,089, filed on Oct. 31, 2019.
Claims priority of provisional application 63/053,723, filed on Jul. 20, 2020.
Claims priority of provisional application 63/192,105, filed on May 24, 2021.
Claims priority of provisional application 63/223,056, filed on Jul. 18, 2021.
Claims priority of provisional application 63/226,761, filed on Jul. 29, 2021.
Prior Publication US 2021/0391370 A1, Dec. 16, 2021
Int. Cl. H01L 27/146 (2006.01); H01L 25/16 (2023.01)

CPC H01L 27/14634 (2013.01) [H01L 25/167 (2013.01); H01L 27/14618 (2013.01); H01L 27/14621 (2013.01); H01L 27/14627 (2013.01); H01L 27/14636 (2013.01)]

15 Claims

1. An optical sensing apparatus, comprising:

a photo-detecting device comprising:

a first substrate comprising a silicon die;

a carrier conducting layer formed in the first substrate;

an absorption region formed in the first substrate and composed of germanium, wherein the absorption region is in contact with the carrier conducting layer, and the absorption region is configured to receive an optical signal and to generate photo-current in response to the optical signal,

wherein the absorption region is doped with a first dopant having a first conductivity type and a first peak doping concentration,

wherein the carrier conducting layer is doped with a second dopant having a second conductivity type and a second peak doping concentration,

wherein the carrier conducting layer is in contact with the absorption region to form at least one heterointerface, and

wherein a ratio between the first peak doping concentration of the absorption region and the second peak doping concentration of the carrier conducting layer is equal to or greater than 10;

an electrode formed over the carrier conducting layer, wherein the electrode is separated from the absorption region, and wherein the electrode is configured to collect a portion of the photo-current;

a second substrate bonded to the first substrate, wherein the second substrate comprises a silicon die; and

first circuitry formed in the second substrate, wherein the first circuitry is configured to convert the portion of the photo-current collected by the electrode to an analog voltage output for processing; and

a third substrate coupled to the photo-detecting device, the third substrate comprising second circuitry configured to process the analog voltage output to generate a digital output,

wherein the first circuitry comprises:

a low-noise preamplifier configured to convert the portion of the photo-current collected by the electrode of the photo-detecting device into the analog voltage output, and

an amplifier configured to amplify the analog voltage output, and

wherein the absorption region comprises an array of pixels that are electrically coupled together to generate one photo-current to be the photo-current.