Recessed U-Shaped Gates for Leakage Control in Dense Peripheral Regions
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Solution Overview
Problem
The scaling down of semiconductor devices poses challenges in achieving improved quality, yield, performance, and reliability while controlling leakage issues associated with smaller gate sizes.
Innovation Solution
The semiconductor device incorporates a substrate with a first peripheral region featuring recessed gates with a U-shaped cross-sectional profile and a second peripheral region with a planar gate structure. The recessed gates include a recessed gate dielectric layer, a bottom conductive layer with a valley-shaped profile, a top conductive layer, and a capping layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If gate size is scaled down to increase element density, then productivity and element density are improved, but leakage control deteriorates
Solution Approach 1:
The gate structure transitions from a planar two-dimensional configuration to a three-dimensional recessed structure. The gate is formed in a recess within the semiconductor substrate, creating vertical depth as an additional dimension. This allows the gate to maintain effective control over the channel while occupying less surface area, thereby increasing element density without compromising leakage control.
Solution Approach 2:
The gate structure is nested within the substrate by forming a recess. The gate electrode and associated layers are positioned within this recessed cavity, effectively nesting the gate structure into the substrate volume rather than occupying only the surface plane. This nesting approach enables higher density while maintaining proper gate-to-channel spacing for leakage control.
2Object-affected harmful factors
If recessed gate structure is implemented to control leakage, then leakage control is improved, but device complexity increases
Solution Approach 1:
The gate structure is segmented into multiple distinct layers: a gate electrode layer, a gate insulator layer, and a capping layer. Each layer serves a specific function and can be independently optimized and fabricated. This segmentation allows for controlled complexity by breaking down the recessed gate into manageable components that can be formed using standard semiconductor processing techniques.
Solution Approach 2:
The recessed gate employs a composite structure with multiple materials serving different functions. The gate electrode may use conductive materials, the gate insulator uses dielectric materials, and the capping layer provides protection. This composite approach enables leakage control through proper material selection and layering while managing overall device complexity through functional specialization.
3Adaptability or versatility
If different gate structures are used in different peripheral regions, then adaptability is improved, but manufacturing complexity increases
Solution Approach 1:
Different gate structures (recessed gates in the first peripheral region versus planar gates in the second peripheral region) are implemented according to local requirements. The first peripheral region with higher element density benefits from recessed gates for leakage control, while the second peripheral region with lower density uses simpler planar gates. This local differentiation optimizes performance for each region's specific needs while managing overall manufacturing complexity.
Solution Approach 2:
The manufacturing process is designed to handle multiple gate structure types within a single fabrication sequence. The same basic process steps can produce both recessed and planar gates depending on local conditions, making the manufacturing system universal and adaptable to different regions without requiring entirely separate process lines, thereby controlling manufacturing complexity.
Data Source
AI summary
The present application discloses a semiconductor device and a method for fabricating the semiconductor device. The semiconductor device includes a substrate including a first peripheral region and a second peripheral region; a plurality of recessed gates respectively including a recessed gate dielectric layer inwardly positioned in the first peripheral region and including a U-shaped cross-sectional profile, a recessed gate bottom conductive layer positioned on the recessed gate dielectric layer and including a valley-shaped cross-sectional profile, resulting in a first valley, a recessed gate top conductive layer conformally positioned on the first valley of the recessed gate bottom conductive layer, and a recessed gate capping layer positioned on the recessed gate top conductive layer; and a peripheral gate structure positioned on the second peripheral region. An element density of the first peripheral region is greater than an element density of the second peripheral region.