US 12,206,032 B2
Wideband back-illuminated electromagnetic radiation detectors
Mark Alan Arbore, Los Altos, CA (US); Matthew T. Morea, Cupertino, CA (US); Miikka M. Kangas, Campbell, CA (US); Romain F. Chevallier, Sunnyvale, CA (US); and Tomas Sarmiento, Mountain View, CA (US)
Assigned to Apple Inc., Cupertino, CA (US)
Filed by Apple Inc., Cupertino, CA (US)
Filed on Jul. 26, 2021, as Appl. No. 17/385,813.
Claims priority of provisional application 63/059,862, filed on Jul. 31, 2020.
Prior Publication US 2022/0037543 A1, Feb. 3, 2022
Int. Cl. H01L 31/0304 (2006.01); H01L 27/144 (2006.01); H01L 31/0203 (2014.01); H01L 31/0232 (2014.01)
CPC H01L 31/03046 (2013.01) [H01L 27/1446 (2013.01); H01L 31/0203 (2013.01); H01L 31/02327 (2013.01)] 21 Claims
OG exemplary drawing
 
1. An electromagnetic radiation detector, comprising:
an indium phosphide (InP) substrate having a first surface opposite a second surface;
a first indium gallium arsenide (InGaAs) electromagnetic radiation absorber stacked on the first surface and configured to absorb a first set of electromagnetic radiation wavelengths;
a set of one or more buffer layers stacked on the first InGaAs electromagnetic radiation absorber and configured to absorb at least some of the first set of electromagnetic radiation wavelengths;
a second InGaAs electromagnetic radiation absorber stacked on the set of one or more buffer layers and configured to absorb a second set of electromagnetic radiation wavelengths; and
an immersion condenser lens formed on the second surface and configured to direct electromagnetic radiation through the InP substrate and toward the first InGaAs electromagnetic radiation absorber and the second InGaAs electromagnetic radiation absorber; wherein,
the second set of electromagnetic radiation wavelengths includes at least some electromagnetic radiation wavelengths that are not in the first set of electromagnetic radiation wavelengths; and
a first responsivity of the first InGaAs electromagnetic radiation absorber and a second responsivity of the second InGaAs electromagnetic radiation absorber have a crossover point at an electromagnetic radiation wavelength within a water absorption band of about 1.85 μm to about 2.0 μm.