Micron Technology Incorporated

Fawad Ahmed

Suraj J Mathew

Kris K Brown

Vinay Nair

Diem Thy N Tran

Raghunath Singanamalla

Fatma Arzum Simsek-Ege

Charles H Dennison

Kunal R Parekh

John K Zahurak

Richard H Lane

Mark Fischer

Haitao Liu

Kamal M Karda

Deepak Chandra Pandey

Gloria Yang

David A Kao

Fernando N Gonzalez

Jigish D Trivedi

Kunal Shrotri

Jeffrey W Honeycutt

Shivani Srivastava

Fatma Arzum Slmsek-Ege

Some embodiments include a memory cell having a first transistor supported by a semiconductor base, and having second and third transistors above the first transistor and vertically stacked one atop the other. Some embodiments include a memory cell having first, second and third transistors. The third transistor is above the second transistor, and the second and third transistors are above the first transistor. The first transistor has first and second source/drain regions, the second transistor has third and fourth source/drain regions, and the third transistor has fifth and sixth source/drain regions. A read bitline is coupled with the sixth source/drain region. A write bitline is coupled with the first source/drain region. A write wordline includes a gate of the first transistor. A read wordline includes a gate of the third transistor. A capacitor is coupled with the second source/drain region and with a gate of the second transistor.

Memory cells and memory arrays

Some embodiments include a memory cell having first, second and third transistors, with the second and third transistors being vertically displaced relative to one another. The memory cell has a semiconductor pillar extending along the second and third transistors, with the semiconductor pillar containing channel regions and source/drain regions of the second and third transistors. A capacitor may be electrically coupled between a source/drain region of the first transistor and a gate of the second transistor.

Some embodiments include methods of forming transistors. Recesses are formed to extend into semiconductor material. The recesses have upper regions lined with liner material and have segments of semiconductor material exposed along lower regions. Semiconductor material is isotropically etched through the exposed segments which transforms the recesses into openings having wide lower regions beneath narrow upper regions. Gate dielectric material is formed along sidewalls of the openings. Gate material is formed within the openings and over regions of the semiconductor material between the openings. Insulative material is formed down the center of each opening and entirely through the gate material. A segment of gate material extends from one of the openings to the other, and wraps around a pillar of the semiconductor material between the openings. The segment is a gate of a transistor. Source/drain regions are formed on opposing sides of the gate.

Methods of forming transistors

Some embodiments include methods of forming silicon dioxide in which silicon dioxide is formed across silicon utilizing a first treatment temperature of no greater than about 1000&#xb0; C., and in which an interface between the silicon dioxide and the silicon is annealed utilizing a second treatment temperature which is at least about 1050&#xb0; C. Some embodiments include methods of forming transistors in which a trench is formed to extend into monocrystalline silicon. Silicon dioxide is formed along multiple crystallographic planes along an interior of the trench utilizing a first treatment temperature of no greater than about 1000&#xb0; C., and an interface between the silicon dioxide and the monocrystalline silicon is annealed utilizing a second treatment temperature which is at least about 1050&#xb0; C. A transistor gate is formed within the trench, and a pair of source/drain regions is formed within the monocrystalline silicon adjacent the transistor gate. Some embodiments include DRAM cells.

DRAM cells and methods of forming silicon dioxide

A double blanket ion implant method for forming diffusion regions in memory array devices, such as a MOSFET access device is disclosed. The method provides a semiconductor substrate with a gate structure formed on its surface Next, a first pair of diffusion regions are formed in a region adjacent to the channel region by a first blanket ion implantation process. The first blanket ion implantation process has a first energy level and dose. The device is subjected to oxidizing conditions, which form oxidized sidewalls on the gate structure. A second blanket ion implantation process is conducted at the same location as the first ion implantation process adding additional dopant to the diffusion regions. The second blanket ion implantation process has a second energy level and dose. The resultant diffusion regions provide the device with improved static refresh performance over prior art devices. In addition, the first and second energy levels and doses are substantially lower than an energy level and dose used in a prior art single implantation process.

Double blanket ion implant method and structure

A method used during the formation of a semiconductor device reduces ion channeling during implantation of the wafer. The method comprises providing a semiconductor wafer and an unetched transistor gate stack assembly over the wafer. The unetched transistor gate stack assembly comprises a gate oxide layer, a control gate layer, a metal layer, and a dielectric capping layer. A patterned photoresist layer is formed over the unetched transistor gate stack assembly, then each of the capping layer, the metal layer, the control gate layer, and the gate oxide layer is etched to form a plurality of laterally-spaced transistor gate stacks. A screening layer is formed overlying the semiconductor wafer between the transistor gate stacks. A dopant is implanted into the semiconductor wafer through the screening layer, then the screening layer is removed.

Sacrificial deposition layer as screening material for implants into a wafer during the manufacture of a semiconductor device

A double blanket ion implant method for forming diffusion regions in memory array devices, such as a MOSFET access device is disclosed. The method provides a semiconductor substrate with a gate structure formed on its surface. Next, a first pair of diffusion regions are formed in a region adjacent to the channel region by a first blanket ion implantation process. The first blanket ion implantation process has a first energy level and dose. The device is subjected to oxidizing conditions, which form oxidized sidewalls on the gate structure. A second blanket ion implantation process is conducted at the same location as the first ion implantation process adding additional dopant to the diffusion regions. The second blanket ion implantation process has a second energy level and dose. The resultant diffusion regions provide the device with improved static refresh performance over prior art devices. In addition, the first and second energy levels and doses are substantially lower than an energy level and dose used in a prior art single implantation process.

Method of improving static refresh

Structure for improving static refresh

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Boise, ID, United States of America

Fawad Ahmed