POET Technologies Inc of San Jose, CA, USA — which has developed the proprietary planar optoelectronic technology (POET) platform for monolithic fabrication of integrated III-V-based electronic and optical devices on a single semiconductor wafer — says that it has taken another significant step toward its goal of developing a fully integrated commercial optoelectronic technology platform.
The specific milestone achieved is the first demonstration of functional heterojunction field-effect transistors (HFETs) down to 250nm effective gate lengths on the same proprietary epitaxy and utilizing the same integrated process sequence that was previously used to demonstrate high-performance detectors. This milestone is the latest in POET's initiative to integrate a detector, HFET and laser together into a single chip, the three key components of POET's current market target of an active optical cable.
"Two of the three critical individual pieces of an integrated optoelectronic product are now in place and undergoing their respective optimization cycles," says chief operating officer Dr Subhash Deshmukh. "As reported earlier, we have encountered delays in completing the VCSEL [vertical-cavity surface-emitting laser] milestone. The VCSEL continues to be our focus, even while we simultaneously make progress on other aspects of the technology," he adds. "The characterization that has been done to date on the VCSEL points to required optimization of a few layers in a very complex and unique epitaxial stack and fine tuning of the resonant cavity mode. The new and optimized epitaxial structure is expected to be delivered to the foundry for processing over the next couple of months," Deshmukh continues. "We have not uncovered any fundamental show-stoppers. We are charting new territory here and, as pointed out at the recent town hall meeting and at the annual meeting of shareholders, technical issues are commonly encountered throughout the R&D process and we are systematically understanding and addressing these issues."
POET has already demonstrated electrical functionality of the VCSEL with desired thyristor characteristics and demonstrated lasing modes through optical pumping of the VCSEL cavity (i.e. light emission was detected on the epitaxial wafer surface). However, in order to enable electrical pumping of the VCSEL, the team has had to re-design some aspects of the epitaxial stack. VCSEL functionality was previously verified in a lab setting and the functionality of that original laser has been re-tested and reconfirmed.
POET's management reaffirms its confidence in its roadmap and progress in the lab-to-fab-to-commercialization of monolithic optoelectronic products. "We will provide the next update around the earnings call, which we intend to schedule for early fourth-quarter 2016," says CEO Dr Suresh Venkatesan.
