Wafertech, Inc.

Waferteh, LLC

Yimin Wang

Raymond Li

A split gate flash cell device with floating gate transistors is provided. Each floating gate transistor is formed by providing a floating gate transistor substructure including an oxide disposed over a polysilicon gate disposed over a gate oxide disposed on a portion of a common source. Nitride spacers are formed along sidewalls of the floating gate transistor substructure and cover portions of the gate oxide that terminate at the sidewalls. An isotropic oxide etch is performed with the nitride spacers intact. The isotropic etch laterally recedes opposed edges of the oxide inwardly such that a width of the oxide is less than a width of the polysilicon gate. An inter-gate dielectric is formed over the floating gate transistor substructure and control gates are formed over the inter-gate dielectric to form the floating gate transistors.

Split gate flash cell semiconductor device

Provided is a floating gate flash cell and method for forming the same. The flash includes two floating gate transistors and a common source area therebetween. Each floating gate transistor includes a floating gate having a central portion disposed over a substrate surface and opposed lateral edges that extend into trenches and below the substrate surface. A control gate is disposed over said floating gate with a control gate dielectric between the floating gate and the control gate. The floating gates have side edges that are orthogonal to the opposed lateral edges and a common source area which is a substrate diffusion area, is positioned between respective facing side edges of the floating gates.

Floating gate flash cell with extended floating gate

A method for forming a split gate flash cell memory device provides for establishing a floating gate region then using spacers or other hard mask materials that cover opposed edges of a gate electrode material in the gate region, to serve as hard masks during an etching operation that partially etches the gate electrode material which may be polysilicon. The gate electrode so produced serves as a floating gate electrode and includes a recessed central portion flanked by a pair of opposed upwardly extending fins which may terminate upwardly at an apex. A floating gate oxide is then formed by thermal oxidation and/or oxide deposition techniques.

Floating gate flash cell device and method for partially etching silicon gate to form the same

Split gate flash cell and method for making the same

A method and structure provide for customizing STI, shallow trench isolation, structures in various parts of a system-on-chip, SOC, or other semiconductor integrated circuit device. Within an individual chip, STI structures are formed to include different dielectric thicknesses that are particularly advantageous for the particular device portion of the SOC chip in which the STI structure is formed.

Methods and structures for customized STI structures in semiconductor devices

A method for forming a split gate flash cell device provides for forming floating gate transistors. Each floating gate transistor is formed by providing a floating gate transistor substructure including an oxide disposed over a polysilicon gate disposed over a gate oxide disposed on a portion of a common source. Nitride spacers are formed along sidewalls of the floating gate transistor substructure and cover portions of the gate oxide that terminate at the sidewalls. An isotropic oxide etch is performed with the nitride spacers intact. The isotropic etch laterally recedes opposed edges of the oxide inwardly such that a width of the oxide is less than a width of the polysilicon gate. An inter-gate dielectric is formed over the floating gate transistor substructure and control gates are formed over the inter-gate dielectric to form the floating gate transistors.

Methods for forming split gate flash cell structures provide for symmetrical cells that are immune to misalignment of the photoresist pattern when forming the control gates. Spacers are utilized to form the floating gates in the floating gate transistors used in the flash cells. The spacers may be oxide spacers used to mask a polysilicon layer that will form the floating gates or the spacers may be polysilicon spacers that will themselves form the floating gates. The inter-gate oxide of the floating gate transistors may be formed using HTO or may be deposited. Hard mask spacers are used in conjunction with the control gate photoresist patterning operation to control the size and configuration of the control gate and the channel length.

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Camas, WA, United States of America

Yimin Wang