Trench Semiconductor Gate Electrode Leakage Reduction
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Solution Overview
Problem
The increasing demand for lighter, smaller, high-speed, multi-functional, high-performance, and low-priced semiconductor devices poses challenges in achieving higher integration density and effective channel length while minimizing gate-induced drain leakage current and electrical shorts.
Innovation Solution
The semiconductor devices incorporate a trench structure with a bulk electrode and a liner electrode, where the liner electrode has a U-shaped cross-section covering the sidewalls and bottom of the trench, and is formed using materials with different etch selectivities, such as titanium nitride and tungsten, to control the effective work function and reduce overlap with source/drain regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the integration density and effective channel length are increased, then the performance and functionality of semiconductor devices are improved, but gate-induced drain leakage current and electrical shorts increase
Solution Approach 1:
The gate electrode is segmented into a bulk electrode and a liner electrode with distinct functions. The bulk electrode provides the primary gate function, while the liner electrode specifically addresses leakage prevention at the gate-source/drain interface, dividing the problem into manageable parts.
Solution Approach 2:
The liner electrode acts as an intermediary layer between the bulk electrode and the source/drain regions. It mediates the electrical interaction by providing a high-work-function barrier that prevents charge leakage while maintaining the necessary electrical connection.
2Ease of manufacture
If the gate electrode structure is simplified, then the manufacturing process is easier, but the ability to control gate-induced drain leakage current is reduced
Solution Approach 1:
The liner electrode and bulk electrode are merged into a single gate electrode structure formed through integrated processing steps. The liner electrode is conformally deposited on the gate dielectric before bulk electrode fill, combining two functional layers into one manufacturable structure.
Solution Approach 2:
The work function parameter is optimized by selecting specific materials for the liner electrode (titanium nitride, tungsten, or tungsten silicide) with work functions greater than 4.5 eV. This parameter change provides the necessary electrical barrier while maintaining compatibility with standard fabrication processes.
3Length of moving object
If the overlapping area between gate electrode and source/drain regions is increased, then the channel width is improved, but gate-induced drain leakage current increases
Solution Approach 1:
The gate electrode structure has non-uniform properties: the liner electrode provides high work function at the critical interface regions near source/drain, while the bulk electrode provides the primary gate control. This local quality differentiation allows wide channel overlap without proportionally increasing leakage.
Solution Approach 2:
The gate electrode is a composite structure combining materials with different work functions. The liner electrode uses high-work-function materials (titanium nitride, tungsten, or tungsten silicide) at the interface, while the bulk electrode uses standard gate materials, creating a composite structure that optimizes both channel width and leakage prevention.
Data Source
AI summary
Semiconductor devices and methods of forming the same may be provided. The semiconductor devices may include a trench in a substrate. The semiconductor devices may also include a bulk electrode within opposing sidewalls of the trench. The semiconductor devices may further include a liner electrode between the bulk electrode and the opposing sidewalls of the trench. The liner electrode may include a sidewall portion between a sidewall of the bulk electrode and one of the opposing sidewalls of the trench.