Newly Patented, Multi-layered “Superlattice-Doped” CMOS Detector Arrays Demonstrate Unique Stability in DUV Conditions.
Alacron, Inc.,a manufacturer of high performance frame grabbers and accelerated frame grabber subsystems for more than 25 years, announced that Dr. Michael Hoenk, lead team member of Alacron’s development partner, the Analytical Instruments Group at Jet Propulsion Laboratory (JPL) and California Institute of Technology, presented their new, patented process and technology at the 2013 Annual International Image Sensors Workshop (IISW), held June 12-16 at Snowbird Resort in Utah, USA.
“The DUV Stability of Superlattice-doped CMOS Detector Array”
Dr. Hoenk was among those selected to present at this year’s IISW. Entitled “The DUV Stability of Superlattice-doped CMOS Detector Array” his presentation makes the case for a new industry term describing JPL’s patented process -- “superlattice doping.” Superlattice doping is ground-breaking both in terms of the physics as well as in the results of its application.
Developed by Hoenk and his team at JPL in concert with Alacron, Inc., superlattice-doping is a new multi-layered 2D alternative to existing passivation processes. Existing passivation processes include single-layer 2D delta doping, and industry-standard 3D doping methods, such as ion implantation and diffusion.
Hoenk’s presentations at IISW compared and contrasted the physics and results of traditional passivation (ion implantation and diffusion), 2D delta doping, and JPL’s newly patented multi-layered 2D, superlattice-doping.
“It is impossible to prevent degradation of single layer 3D doped surfaces (ion implantation), whereas the physics of multi-layered 2D, superlattice-doping confirm the experimental results -- insensitivity to surface states,” Hoenk says. “The addition of multiple layers significantly increases the durability without sacrificing QE [Quantum Efficiency].”
Hoenk explained to IISW attendees the special properties of superlattice-doped detectors. Experiments and calculations show that quantum-engineered surfaces, grown at JPL by low temperature molecular beam epitaxy, achieve a qualitative as well as quantitative uniqueness in their near-immunity to high densities of surface and interface traps.
Significance of Super-Lattice Doped Sensors To The Semiconductor Industry
For decades, electronics industry developers and semiconductor manufacturers have been seeking a more durable deep UV solution to the challenges of quality assurance, especially for the inspection of minute silicon wafers. Until now, back-illuminated detectors (also known as BSI -- #BSI #BackIlluminatedDetectors) have been more susceptible to damage, because process constraints limit back surface passivation processes to relatively low temperatures and energies.
“The resulting surface and interface traps are subject to time and temperature-dependent charging and discharging phenomena,” Hoenk explains. “This gives rise to both temporary and permanent changes in quantum efficiency and dark current in back-illuminated imaging detectors.”
“These superlattice-doped detectors are the only imaging detectors known to have survived direct, long-term irradiation by deep ultraviolet (DUV) excimer lasers with no measurable degradation in performance,” Hoenk emphasizes.
JPL and Alacron recently demonstrated a high-speed CMOS camera capable DUVimaging with high QE and exceptional stability and long-term reliability. At IISW, Hoenk referenced the initial development efforts with Alacron to illustrate the first laser exposure of superlattice-doped wafers.
In his presentation at IISW, Hoenk used diagrams to illustrate the physics and chemistry of doped silicon surfaces, and the principles of quantum engineering that underlie the unique capabilities of superlattice-doped detectors, all which differentiate the new process and resulting technology.
Alacron’s CEO, Dr. Joseph Sgro, emerged from the fields of neurology and advanced mathematics to found Alacron in 1985. Prior to this project with Hoenk and the team at JPL, Sgro and Alacron pioneered many R&D initiatives, always seeking solutions for challenging, real-world problems, resulting in integrated designs and product applications in the fields of medicine, military and manufacturing.
About this most recent development project, Sgro says, “I am pleased to have partnered with Dr. Hoenk and his team at JPL to incorporate their innovative, patented superlattice-doped, AR processes into Alacron’s BSI product, which should prove to be game changer for semiconductor manufacturers, and eventually many other industries within markets such as medical, manufacturing, military, and space exploration.”
Alacron’s CEO, Dr. Joseph Sgro, concludes, “This evidence of damage underscores the data showing the DUV stability of the new multi-layered, 2D delta doped sensors, and proving that JPL’s, patented superlattice-doped surfaces for BSI sensors are insensitive to surface traps.”