American Semiconductor Corporation

Dale G Wilson

Douglas R Hackler, Sr

Stephen A Parke

Kelly James DeGregorio

Three-dimensional flexible photonic integrated circuits on silicon are fabricated in semiconductor wafer form and then transferred to Silicon-on-Polymer (SOP) substrates. SOP provides flexibility for conformal mounting with devices capable of maintaining performance when dynamically deformed to allow routing of light in x, y and z directions. Bonding a wafer or individual die of III-V semiconductor, such as Gallium Arsenide or similar photonic material, to the flexible silicon creates an active region for lasers, amplifiers, modulators, and other photonic devices using standard processing. Mounting additional photonic devices to the opposite side of a flexible photonic waveguide produces a stack for three-dimensional devices. Multiple flexible photonic waveguides may be stacked to increase functionality by transferring light between stacked waveguides. The flexible photonic circuit allows for integration of photonic devices such as low threshold lasers, tunable lasers, and other photonic integrated circuits with flexible Complementary Metal Oxide Semiconductor (CMOS) integrated circuits.

Flexible 3-D photonic device

This method of waferscale packaging produces finished integrated circuits (ICs) individually completely encapsulated with environmentally protective packaging material while still in the wafer format. Following conventional semiconductor fabrication of chips at the wafer level and prior to their separation, a first polymer is applied to the front surface of the wafer with allowance for contact holes. A carrier wafer is attached to the exposed polymer. The original substrate is removed and the devices are separated by cutting through the semiconductor layer and the first polymer. A second polymer is applied to cover the exposed backside of the devices and to fill the cut spaces between them, thereby sealing the remaining five surfaces of the chips. The second polymer layer may also include contact holes for access to the back side of the device chips. A second singulation cutting leaves the chips on the wafer prepared for a pick-and-place operation.

Method of producing encapsulated IC devices on a wafer

Memory cells are constructed from double-gated four terminal transistors having independent gate control. DRAM cells using one transistor to implement a Ferroelectric FeRAM are described. Top gates provide conventional access while independent bottom gates provide control to optimize memory retention for given speed and power parameters as well as to accommodate hardening against radiation. In a single transistor cell without a capacitor, use of the bottom gate allows packing to a density approaching 2 F. Using a ferroelectric material as the gate insulator produces a single-transistor FeRAM cell that overcomes the industry-wide Write Disturb problem. The memory cells are compatible with SOI logic circuitry for use as embedded RAM in SOC applications.

Single transistor memory with immunity to write disturb

Memory cells are constructed from double-gated four terminal transistors having independent gate control. DRAM cells may use one, two or three transistors. Single transistor cells are constructed either with or without a bit storage capacitor, and both NAND- and NOR-type Non-Volatile NVRAM cells, as well as Ferroelectric FeRAM cells, are described. For all cells, top gates provide conventional access while independent bottom gates provide control to optimize memory retention for given speed and power parameters as well as to accommodate hardening against radiation. In a single transistor cell without a capacitor, use of the bottom gate allows packing to a density approaching 2 F. The memory cells are compatible with SOI logic circuitry for use as embedded RAM in SOC applications.

Double-gated transistor memory

Memory cells are constructed from double-gated four terminal transistors having independent gate control. DRAM cells may use one, two or three transistors. Single transistor cells are constructed either with or without a bit storage capacitor, and both NAND- and NOR-type Non-Volatile NVRAM cells, as well as Ferroelectric FeRAM cells, are described. For all cells, top gates provide conventional access while independent bottom gates provide control to optimize memory retention for given speed and power parameters as well as to accommodate hardening against radiation. In a single transistor cell without a capacitor, use of the bottom gate allows packing to a density approaching 2 F. Using a ferroelectric material as the gate insulator produces a single-transistor FeRAM cell that overcomes the industry-wide Write Disturb problem. The memory cells are compatible with SOI logic circuitry for use as embedded RAM in SOC applications.

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Kuna, ID, United States of America

Dale G Wilson