Recessed Access Device Narrow Channel Leakage Control
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Solution Overview
Problem
Conventional recessed access devices face a tradeoff between high doping concentrations for improved drive current performance and low doping concentrations to reduce current leakage, with existing designs struggling to achieve both high performance and low leakage effectively.
Innovation Solution
The design incorporates a channel region with a narrower width than the source and drain pillars, allowing for higher doping concentrations while minimizing current leakage by ensuring the gate surrounds the channel region on three sides, thereby enhancing control and reducing leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If higher doping concentration is used in the channel region, then drive current performance is improved, but current leakage increases
Solution Approach 1:
The patent applies local quality by creating a channel region with narrower width compared to the source and drain regions. This localized dimensional change allows higher doping concentration to be confined specifically in the channel region, improving drive current while the narrower dimensions simultaneously restrict leakage paths. The gate structure surrounding the channel on three sides further enhances this localized control of electrical properties.
Solution Approach 2:
The patent changes the width parameter of the channel region, making it narrower than the source and drain pillars. This parameter change enables the channel to support higher doping concentrations while maintaining lower leakage. The width reduction is a key parameter modification that resolves the contradiction between drive current and leakage by altering the geometric dimensions that control both properties.
2Power
If the channel region width is reduced, then doping concentration can be increased for better performance, but manufacturing precision requirements increase
Solution Approach 1:
The patent moves the access device to a vertical orientation, offsetting it vertically from the storage element rather than horizontally. This dimensional reorganization allows the channel region to be narrow in the horizontal plane while maintaining sufficient vertical dimensions for manufacturing. The vertical offset configuration enables precise width control through standard lithographic processes while achieving the desired narrow channel for high doping concentration.
Data Source
AI summary
A semiconductor device comprises a recessed access device that includes a first pillar, a second pillar, a channel region connecting the first and second pillars, and a gate disposed over the channel region. The channel region has a width that is narrower than widths of the first pillar and the second pillar. An array of recessed access devices comprises a plurality of pillars protruding from a substrate, and a plurality of channel regions. Each channel region has a width that is less than about 10 nm and couples neighboring pillars to form a plurality of junctionless recessed access devices. A method of forming at least one recessed access device also comprises forming pillars over a substrate, forming at least a channel region coupled with the pillars, the channel region having a relatively narrow width, and forming a gate at least partially surrounding the channel region on at least three sides.