Advanced Detectors, Systems, & Nanoscience
MDL Superlattice-Doped Detectors Provide Unprecedented Stability and Performance
Despite over 40 years of development, backside-illuminated detectors are not sufficiently stable for many applications. MDL has developed superlattice-doped detectors with exceptional stability and quantum efficiency (QE) in the deep and far-UV. Superlattice doping represents a fundamentally different approach to surface passivation than conventional methods of ion implantation and diffusion. The structure of the superlattice comprises multiple layers of delta-doped silicon grown by molecular-beam epitaxy. Its stability enables nearly 100% charge collection efficiency independent of the density of interface traps.
MDL recently partnered with Alacron, Inc. to develop a high-speed imaging camera in which superlattice-doped CMOS imaging detectors provide the essential stability and sensitivity for deep ultraviolet (DUV) lithography applications in the semiconductor industry. The detectors achieve nearly 100% internal QE in the deep and far-UV with a 64% external QE at 263 nm. In lifetime tests performed at Applied Materials, the QE and dark current of the camera remained stable to better than 1% precision during long-term exposure to several billion laser pulses, with no measurable degradation, no blooming, and no image memory at 1000 fps.
MDL is now working with industry and university partners on further development and applications of superlattice-doping technology for DUV lithography, electron microscopy, and high-sensitivity photon and particle detection.