Semiconductor Gate Structure with Continuous Diffusion Isolation
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Solution Overview
Problem
Semiconductor devices face reliability degradation due to leakage current and dielectric breakdown in gate structures, particularly in state-of-the-art technology nodes, which affects their quality and performance in applications like autonomous driving and 5G cellular communications.
Innovation Solution
The implementation of a continuous diffusion (CNOD) structure with a core gate and isolation gates, where the isolation gates have a thicker dielectric layer than the core gate, effectively reducing leakage currents and preventing electrical breakdown by enhancing electrical isolation between transistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a thin dielectric layer is used in the core gate to improve electrical performance, then device speed and efficiency are improved, but leakage current increases and dielectric breakdown risk increases
Solution Approach 1:
The gate structure is segmented into a core gate with a thin dielectric layer for high-speed performance and isolation gates with thick dielectric layers for reliability. This segmentation allows each gate type to be optimized independently, with the core gate providing speed and the isolation gates providing protection against leakage and breakdown.
Solution Approach 2:
Different dielectric layer thicknesses are applied to different locations: the core gate uses a thin dielectric layer (first thickness) for optimal electrical performance, while the isolation gates use a thick dielectric layer (second thickness greater than first thickness) for enhanced isolation and reliability. This local differentiation resolves the contradiction between speed and reliability.
2Reliability
If isolation gates with thicker dielectric layers are added to reduce leakage current, then reliability is improved, but device complexity increases
Solution Approach 1:
The isolation gates serve multiple functions: they provide electrical isolation between adjacent devices, reduce leakage currents, and prevent dielectric breakdown. By combining these functions into a single structural element with a thick dielectric layer, the solution achieves reliability improvement without proportionally increasing complexity.
Solution Approach 2:
The isolation gates are merged with the core gate structure to form an integrated gate system. The isolation gates are positioned between the core gate and adjacent devices, combining isolation functionality with the gate structure itself rather than adding separate isolation components.
3Reliability
If continuous diffusion structure is implemented to electrically isolate devices, then leakage current is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The continuous diffusion structure is formed as a preliminary step before gate fabrication. By establishing the diffusion-based electrical isolation structure in advance, the subsequent gate formation processes can proceed with standard precision requirements, rather than requiring high precision during multiple later steps.
Data Source
AI summary
A semiconductor device includes a core gate and a pair of isolation gates. The core gate has a first stack of two or more layers, the first stack including at least (i) a first dielectric layer having a first thickness and (ii) a first electrode layer. The isolation gates are formed on first and second sides of the core gate. The isolation gates are configured to electrically isolate the core gate. At least one of the isolation gates has a second stack of two or more layers, the second stack including at least (i) a second dielectric layer having a second thickness greater than the first thickness and (ii) a second electrode layer.