US 12,255,222 B2
LED array and method of forming a LED array
Andrea Pinos, Plymouth (GB); Xiang Yu, Plymouth (GB); Simon Ashton, Plymouth (GB); and Jonathan Shipp, Plymouth (GB)
Assigned to Plessey Semiconductors Limited, Plymouth (GB)
Appl. No. 17/632,281
Filed by PLESSEY SEMICONDUCTORS LIMITED, Plymouth (GB)
PCT Filed Jul. 24, 2020, PCT No. PCT/EP2020/071024
§ 371(c)(1), (2) Date Feb. 2, 2022,
PCT Pub. No. WO2021/023532, PCT Pub. Date Feb. 11, 2021.
Claims priority of application No. 1911246 (GB), filed on Aug. 6, 2019.
Prior Publication US 2022/0293673 A1, Sep. 15, 2022
Int. Cl. H01L 27/15 (2006.01); H01L 23/485 (2006.01)
CPC H01L 27/156 (2013.01) [H01L 23/485 (2013.01)] 24 Claims
OG exemplary drawing
 
1. A method of forming an LED array precursor comprising:
forming a first LED stack on a substrate surface of a substrate, the first LED stack comprising a plurality of first Group III-nitride layers defining a first semiconductor junction configured to output light having a first wavelength, wherein a n-type side of the semiconductor junction is orientated towards to the substrate surface;
forming a p++ layer on the first LED stack, the p++ layer comprising a Group III-nitride;
selectively removing a portion of the first LED stack;
forming a n++ layer over the substrate to cover the p++ layer, wherein a tunnel junction is formed at an interface between the n++ layer and the p++ layer, the n++ layer comprising a Group III-nitride;
wherein the n++ layer is formed over the substrate surface such that a first portion of the n++ layer covers a first portion of the first LED stack provided on a first portion of the substrate surface and a second portion of the n++ layer covers a second portion of the substrate on which the first LED stack has been selectively removed;
forming a second LED stack on the n++ layer; the second LED stack comprising a plurality of second Group III-nitride layers defining a second semiconductor junction configured to output light having a second wavelength different to the first wavelength, wherein a n-type side of the semiconductor junction is provided closest to the n++ layer,
wherein the method further comprises a step of:
selectively removing a portion of the second LED stack on the substrate surface in order to define:
a first portion of the LED array in which the second LED stack is selectively removed comprising:
the first portion of the first LED stack;
a first portion of the p++ layer; and
the first portion of the n++ layer such that a tunnel junction is provided on the first portion of the first LED stack; and
a second portion of the LED array comprising:
the second portion of the n++ layer; and
a first portion of the second LED stack provided on the second portion of the n++ layer.