Texas Instruments Corporation

Bing W Shen

Robert R Doering

William F Richardson

Ih-Chin Chen

Clarence W Teng

Ashwin H Shah

James G Bohlman

Hun-Lian Tsai

Mark Bordelon

A dRAM memory cell structure and a method for forming the same is disclosed. Each memory cell is formed at a pillar, where the storage plate is an inversion region created by a field plate surrounding all sides of each pillar and separated therefrom by a storage dielectric film. The field plate is formed in a grid shape, and is disposed at the bottom of the trenches surrounding the array of pillars to serve as the fixed plate for all storage capacitors in the array. At the top of each pillar is a diffusion to which the bit lines are connected. Disposed in the trench above the field plate and extending in one direction are word lines. Each word line is formed of a polysilicon filament onto which tungsten is deposited by way of selective CVD. The word line is formed closely adjacent the pillars in its associated row, separated therefrom by a gate dielectric film; the word line is separated from the adjacent row by a dielectric film which is thicker than the gate dielectric, so that the word line will cause conduction between the inversion region and the top diffusion for its associated row, but not for the adjacent row.

High performance composed pillar dRAM cell

A DRAM memory cell structure and a method for forming the same is disclosed. Each memory cell is formed at a pillar, where the storage plate is an inversion region created by a field plate surrounding all sides of each pillar and separated therefrom by a storage dielectric film. The field plate is formed in a grid shape, and is disposed at the bottom of the trenches surrounding the array of pillars to serve as the fixed plate for all storage capacitors in the array. At the top of each pillar is a diffusion to which the bit lines are connected. Disposed in the trench above the field plate and extending in one direction are word lines. Each word line is formed of a polysilicon filament onto which tungsten is deposited by way of selective CVD. The word line is formed closely adjacent the pillars in its associated row,, separated therefrom by a gate dielectric film; the word line is separated from the adjacent row by a dielectric film which is thicker than the gate dielectric, so that the word line will cause conduction between the inversion region and the top diffusion for its associated row, but not for the adjacent row.

High performance composed pillar DRAM cell

A dRAM memory cell structure and a method for forming the same is disclosed. Each memory cell is formed at a pillar, where the storage plate is an inversion region created by a field plate surrounding all sides of each pillar and separated therefrom by a storage dielectric film. The field plate is formed in a grid shape, and is disposed at the bottom of the trenches surrounding the array of pillars to serve as the fixed plate for all storage capacitors in the array. At the top of each pillar is a diffusion to which the bit lines are connected. Disposed in the trench above the field plate and extending in one direction are word lines. Each word line is formed of a polysilicon filament onto which tungsten is deposited by way of selective CVD. The word line is formed closely adjacent the pillars in its associated row, separated therefrom by a gate dielectric film, the word line is separated from the adjacent row by a dielectric film which is thicker than the gate dielectric, so that the word line will cause conduction between the inversion region and the top diffusion for its associated row, but not for the adjacent row.

Method of making high performance composed pillar dRAM cell

An improved memory cell layout (54) is formed including a trench cell (60) formed in a semiconductor substrate (58). The memory cell layout (54) includes a bitline (56) and a wordline (62) for storing and accessing charge. The charge is stored on a capacitor formed from a conductor (68), an insulating region (70) and a semiconductor substrate (58). Bitline (56) is primarily tangential to a trench cell (60), or may surround the periphery thereof. A wordline (62) overlies trench cell (60) and extends therein, and further may be formed of a width narrower than trench cell (60).

Trench memory cell

A capacitor, and a method for making the same, are disclosed, wherein one plate of the capacitor comprises silicon. The dielectric material of the capacitor includes a silicon nitride layer disposed adjacent the silicon plate, and a layer of yttrium oxide disposed thereover. The second plate of the capacitor is formed over the yttrium oxide layer. The silicon nitride provides a barrier to the diffusion of silicon into the yttrium oxide film if the structure is heated, providing for a high dielectric constant capacitor dielectric which has improved leakage characteristics.

Stacked insulating film including yttrium oxide

An integrated circuit capacitor is disclosed which has improved leakage and storage characteristics. The dielectric material for the capacitor consists of a first layer of silicon nitride adjacent the lower plate, such as a silicon substrate, upon which a layer of silicon dioxide is formed. A second layer of silicon nitride is formed over the silicon dioxide layer, above which the second plate is formed. The layer of silicon dioxide may be formed by the partial oxidation of the first silicon nitride layer. The capacitor may be a planar capacitor, may be formed in a trench, or may be formed between two layers above the surface of the substrate.

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Richardson, TX, United States of America

Bing W Shen