Focal plane arrays in type II-superlattices
The subject invention comprises a type-II superlattice photon detector and focal planes array and method for making. The device may be either a binary or tertiary system with a type-II band alignment.
1. A method of preparing an infrared detector comprising the steps of:
a) growing a type-II superlattice structure on a GaSb substrate;
b) fabricating detector pixels;
c) passivating the detector pixels with a passivation layer;
d) patterning and etching the passivation layer;
e) preparing metallic contacts;
f) fabricate indium bumps;
g) flip-chip bonding the substrate with a Si-based ROIC on a ROIC substrate or GaAs or InP based ROIC on a ROIC substrate; and
h) underfilling between the substrate and the ROIC substrate; thereby creating an infrared Focal Plane Array detector based on a type-II superlattice.
2. The method of claim 1 further including the steps of bonding the detector to a ceramic chip carrier.
3. The method of claim 1 wherein the step of growing a type-II superlattice is conducted by MBE or MOCVD.
4. The method of claim 1 wherein the detector pixels are fabricated by UV-photolithography.
5. The method of claim 1 wherein the detector is passivated with SiO 2 or Si 3 N 4 .
6. The method of claim 1 wherein the metallic contacts are prepared by lift-off or etch-back technique.
7. The method of claim 1 wherein the indium bumps are fabricated by direct evaporation or by lift off.
8. The method of claim 1 wherein the substrate is thinned or removed after the underfill step.