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The science behind POET technologies. Requiring Edit in order to keep the content subjective.

POET’s goal of implementing complex, multi-functional optoelectronic subsystems in one serial manufacturing process is expected to be achieved at less cost than competing products built using hybrid technology

The key elements to be integrated in the POET process, all targeted to be simultaneously available for design, are: ·                 The Optical Thyristor ·                 Complementary High Electron Mobility Transistors and Heterojunction Bipolar Transistors ·                 Dielectric Isolation. Optical Thyristor The OT is the backbone of the development of the POET platform. The OT is a multiple-use, four-terminal device having both optical and electrical inputs and optical and electrical outputs. Depending on application and design, an OT could be a (i) laser, (ii) an optical amplifier, (iii) a photoreceiver, or (iv) have multiple electrical operations, as detailed below. An additional anticipated aspect of the POET OT in development is a process step that allows for emission and reception of light in-plane, parallel to the chip surface. Lasers and photoreceivers may either be designed with vertical emission, or use this step to have in-plane emission. This step would allow on-chip optical interconnections and would also support a low-cost multiple-fiber attachment system that the Company has designed. Various modifications of the basic POET epitaxial structure are being designed to support emission or reception at wavelengths of 980, 1310 or 1550 nanometeres. ODIS’s structure and fabrication also is being developed to provide detection and emission from the 3 to 20 micrometer band via the attributes of its quantum well structure. OT Lasers POET lasers are being developed to be a third-generation fabrication that uses an implant confinement technique and improve efficiency and reliability over the proton-confined and oxide-confined devices currently available. Either vertical emission or in-plane emission are anticipated to be employed, depending on design needs. When the in-plane feature is employed, vertical cavity lasers are formed in stripe geometries and have end emission. Such vertical cavity traveling wave lasers have ratios of peripheral length to active area higher than conventional circular vertical-cavity surface-emitting lasers, thus dissipating power more readily and resulting in higher reliability components having longer life. All POET lasers are being developed to be driven by a logic voltage signal, further lowering power requirements and increasing efficiency.

OT Photoreceivers As photoreceivers, OTs have high sensitivity, are self-contained and do not require trans impedence amplifiers, which convert current to voltage to produce usable outputs. Incident light of adequate intensity will produce a direct electrical logic signal. Semiconductor optical amplification provides signal gain and the OT provides the thresholding function. All optical OT structures can be made selectively as transmitters or photoreceivers, further adding to POET IC flexibility. The in-plane emission feature of POET allows easy connection to on-chip passive waveguides. This waveguide technology design features enlarged waveguide apertures to facilitate ease of coupling to single mode fibers with low device insertion loss. This feature is also part of POET’s low-cost multiple fiber attachment technology via waveguides. We are developing a packaging technology that we anticipate will match this horizontal input/output coupling in order to further maintain the cost-effective approach. OT Electrical Applications The POET OT is being developed to also act as an electronic device in memory, digital logic and millimeter-wave oscillator applications. OTs can form single-device static random-access memory cells and can be designed for bistable logic uses. An OT with an optical cavity forms a low-noise voltage controlled oscillator. The ability for OTs to act as comparators is important for high speed analog-to-digital converter designs. The POET platform is targeted to enable manufacturers to develop the internal components required within their product offerings (e.g., handhelds and laptops) to be more reliable, operate faster, and operate for longer periods of time. Transistors POET transistors are designed to suit a wide range of high-performance needs. Electronic designs are expected to be performed using an arbitrary mix of complementary Heterojunction Bipolar Transistors (“HBT”) or complementary High Electron Mobility Transistors (“HEMT”). Complementary HEMT Transistors The POET process is being designed to offer both p-channel and n-channel HEMT devices with complementary threshold voltages. These devices are expected to be usable in both low-noise radiofrequency applications and in high-speed, low power logic applications. Complementary HEMT logic has a potential speed-power ratio above that of silicon CMOS, owing to the higher mobility of the HEMT structure, and can form very low power logic running at speeds to over 100 GHz. This flexibility facilitates the integration of dense logic circuitry with low power, high speed and small size, which allows the combined inclusion of analog circuits and logic circuits in an IC design, which can improve system performance. Complementary HBT Transistors Complementary HBT devices can amplify high-power, high-frequency signals. HBTs find use in high-frequency power amplifiers such as the ones found in cellular phones. Unlike current GaAs processes, the POET process is being developed to allow fabrication of complimentary HBTs. Once implemented, POET platform technology could benefit the consumer by extending battery life and reducing the number of internal components required in a product, thereby reducing its manufacturing cost and increasing product reliability. Dielectric Isolation One of the POET design elements anticipated to support effective optoelectronic integration is high-quality dielectric isolation (“DI”). DI “islands” are formed by a deep trench etch through the entire epitaxial structure into the substrate. Under each active “island” is a layer of oxide produced in the process step in which the lower mirrors are formed. The electrical coupling path between such dielectric “islands” is through the oxide of one region, through a semi-insulating substrate, then through the oxide of another island. This DI produces a much higher isolation than the reverse-junction and deep trench isolations of silicon. High-quality isolation is a principal factor in our being able to produce mixed-signal designs such as optoelectronic transceivers. Without this isolation, resulting crosstalk between the more sensitive receive section and the higher-powered transmit section can cause implementation problems. POET DI is being designed to greatly reduce such problems.