US 12,245,444 B2
Upright photovoltaic cell with front contacts
Philip T. Chiu, La Crescenta, CA (US); Dhananjay M. Bhusari, Santa Clarita, CA (US); and Richard Thai, Woodland Hills, CA (US)
Assigned to The Boeing Company, Arlington, VA (US)
Filed by The Boeing Company, Chicago, IL (US)
Filed on Sep. 29, 2021, as Appl. No. 17/449,421.
Prior Publication US 2023/0335653 A1, Oct. 19, 2023
Int. Cl. H01L 31/18 (2006.01); H10F 10/142 (2025.01); H10F 10/161 (2025.01); H10F 10/19 (2025.01); H10F 71/00 (2025.01); H10F 77/20 (2025.01); H10F 77/70 (2025.01); H01L 31/0224 (2006.01); H01L 31/0236 (2006.01); H01L 31/0687 (2012.01); H01L 31/0725 (2012.01); H01L 31/078 (2012.01)
CPC H10F 77/211 (2025.01) [H10F 10/142 (2025.01); H10F 10/161 (2025.01); H10F 10/19 (2025.01); H10F 71/127 (2025.01); H10F 71/137 (2025.01); H10F 77/707 (2025.01)] 17 Claims
OG exemplary drawing
 
1. A method for fabricating an upright photovoltaic cell having a front side and first and second contacts arranged on the front side, the method comprising:
growing a first epitaxial layer on a substrate, thereby forming a diffused active junction on the substrate;
growing one or more additional epitaxial layers on the substrate, thereby forming one or more additional active junctions above the diffused active junction;
selectively etching an areal region of the first and one or more additional epitaxial layers, thereby forming a mesa on the substrate and exposing a substrate-contact region parallel to the areal region at a base of the mesa;
depositing contact material onto the substrate-contact region, to form the first contact, and concertedly onto a mesa-contact region of the mesa, to form the second contact; and
lifting off the contact material outside of the substrate- and mesa-contact regions, wherein etching the mesa, depositing the contact material, and lifting off the contact material provides a standoff between the mesa and the first contact.