Backside GAA Transistor Structure for Reliable Semiconductor Scaling
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Solution Overview
Problem
The challenge of forming reliable semiconductor devices at smaller sizes is exacerbated by the increasing complexity and difficulty of fabrication processes as feature sizes continue to decrease, necessitating innovative solutions to maintain device reliability and efficiency.
Innovation Solution
The development of gate all around (GAA) transistor structures, which are patterned using photolithography and self-aligned processes, allowing for smaller pitch creation and integration of through-silicon vias as transistors, enabling power gating without area sacrifice, and utilizing high-k dielectric materials for improved stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If feature sizes continue to decrease to increase functional density, then production efficiency and cost are improved, but fabrication process difficulty and device reliability worsen
Solution Approach 1:
The patent transitions from planar 2D transistor structures to three-dimensional FinFET structures with gate-all-around configuration. This dimensional change enables better electrostatic control and carrier confinement in the channel, improving device reliability at scaled dimensions while maintaining high functional density for productivity
Solution Approach 2:
The patent employs high-k dielectric materials (such as HfO2, HfSiO, HfSiON) combined with metal gate electrodes to form composite gate structures. This composite approach enables effective gate control at reduced feature sizes while maintaining device reliability, resolving the contradiction between scaling for productivity and reliability maintenance
2Productivity
If feature sizes continue to decrease to increase functional density, then production efficiency and cost are improved, but fabrication process complexity worsens
Solution Approach 1:
The patent employs preliminary patterning steps including mandrel formation, spacer deposition, and pre-defined etch masks before final transistor structure creation. These preliminary actions establish self-aligned references that simplify subsequent fabrication steps, reducing overall process complexity despite advanced device geometry requirements
Solution Approach 2:
The patent implements nested fabrication sequences where inner transistor structures are formed within outer defined regions, with multiple patterning cycles nested within each other. This nested approach organizes complex fabrication into manageable hierarchical steps, reducing process complexity while achieving high functional density
3Stability of the object's composition
If gate all around structures are formed to improve device stability, then device performance is improved, but fabrication complexity increases
Solution Approach 1:
The patent utilizes self-aligned fabrication processes where previously deposited structures automatically serve as alignment references for subsequent steps. For example, spacers automatically define gate positions, and gate structures automatically define source/drain regions. This self-service approach reduces the need for additional alignment steps, lowering fabrication complexity while achieving gate-all-around configurations for improved stability
Solution Approach 2:
The patent segments the gate structure formation into distinct modular steps: mandrel deposition, spacer formation on mandrels, mandrel removal, and gate material deposition. This segmentation transforms the complex gate-all-around structure creation into manageable sequential steps, reducing fabrication complexity while maintaining device stability
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach facilitates the fabrication of reliable semiconductor devices with high stability and reduced footprint, maintaining device performance and efficiency in smaller geometries.
Implementation Method 1
The development of gate all around (GAA) transistor structures, which are patterned using photolithography and self-aligned processes
Implementation Method 2
utilizing high-k dielectric materials for improved stability
Data Source
AI summary
The present disclosure provides a semiconductor device. The semiconductor device includes a substrate and a transistor in the substrate. The transistor includes a gate structure penetrating through the substrate, a first source/drain region at a front side of the substrate, and a second source/drain region at a back side of the substrate.