Multispectral Sensor/Focal Plane Array Composed of Stacked Thin Film Metal-Semiconductor-Metal Photodetectors

Period of Performance: 05/07/1998 - 11/06/1998


Phase 1 SBIR

Recipient Firm

Tacan Corp.
2330 Faraday Ave
Carlsbad, CA 92008
Principal Investigator

Research Topics


Epitaxial liftoff and grafting technologies offer excellent opportunities for new compact designs of multispectral optical sensing devices covering simultaneously two or more bands across the visible and the near-, mid-, and long-wavelength infrared regimes. Epitaxial liftoff technology can be used to separate the thin epitaxial semiconductor layers containing metal-semiconductor-metal photodetector devices from their epitaxial growth substrates. These thin films (less than 1 mm thick) can then be stacked by grafting techniques onto host substrates in a variety of ways to provide increased functionality without the impediments of lattice mismatches between the membranes. Thus, photodetectors from different materials systems, each tailored for specific wavelength sensing, can be aligned and laminated over each other creating efficient multispectral sensors which collect spectral and spacial data simultaneously. Each semiconductor membrane layer can have its own amplifier/processor, and be individually accessible. This concept can be easily extended to focal-plane array applications. Already at TACAN Corporation, thin film membranes of various semiconductors containing arrays of more than 100 active photodetector devices have been grafted onto a variety of host substrates. By using transparent polyimide separators, independent operation of each level of stacked thin film arrays of photodetectors can provide simultaneous multispectral images.