Buried Gate Transistor Structure for DRAM Integration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The miniaturization of transistors in DRAMs leads to difficulties in patterning the STI structure, deterioration of transistor characteristics due to the short channel effect, and increased contact resistance, which affects the integration and performance of semiconductor devices.
Innovation Solution
A semiconductor device with a buried gate transistor structure, featuring a semiconductor substrate with grooves for isolation and gate electrodes, where the insulating films and gate insulating films are designed to manage threshold voltage and impurity concentration to reduce junction leakage current and enhance current driving capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If transistor miniaturization is pursued to increase integration, then device density improves, but patterning difficulty increases and transistor characteristics deteriorate
Solution Approach 1:
The transistor structure is segmented into multiple functional regions including source region, drain region, channel region, and buried gate region. This segmentation allows each region to be independently optimized and formed through separate processing steps, enabling precise control over transistor characteristics while maintaining miniaturization benefits
Solution Approach 2:
Different regions of the transistor are assigned different impurity concentrations and structural properties. The source and drain regions have high impurity concentrations for low resistance contacts, while the channel region maintains lower impurity for proper transistor switching characteristics. This local differentiation enables optimal performance at each location despite overall miniaturization
2Quantity of substance
If transistor size is reduced to increase integration, then device density improves, but contact resistance increases
Solution Approach 1:
The source and drain regions are formed with high impurity concentrations before the channel region is fully defined. This preliminary formation of low-resistance contact regions ensures that even as the overall transistor size is reduced, the contact areas maintain sufficiently low resistance for reliable operation
Solution Approach 2:
The impurity concentration parameter is varied spatially within the transistor structure. High impurity concentrations are introduced in the source and drain regions to reduce contact resistance, while the channel region maintains appropriate impurity levels for switching functionality, enabling simultaneous optimization of both contact quality and transistor performance
3Quantity of substance
If transistor dimensions are miniaturized to increase integration, then device density improves, but short channel effect increases
Solution Approach 1:
The transistor structure extends into the vertical dimension with the buried gate positioned at a depth below the surface. This three-dimensional configuration allows the channel length to be effectively increased in the vertical direction while maintaining small lateral dimensions, thereby reducing short channel effects while preserving high integration density
Solution Approach 2:
The transistor structure combines multiple materials with different electrical properties including doped semiconductor regions, insulating materials for isolation, and conductive materials for gates and contacts. This composite structure enables precise control of electrical characteristics to mitigate short channel effects while maintaining miniaturized dimensions
Data Source
AI summary
A semiconductor device includes a semiconductor device may include, but is not limited to, a semiconductor substrate, an isolation electrode, a gate electrode, a gate insulating film, and a first insulating film. The semiconductor substrate has a first groove and a second groove. An isolation electrode is positioned in the first groove. The gate electrode is positioned in the second groove. The gate insulating film is adjacent to the gate electrode. The first insulating film is adjacent to the isolation electrode. The isolation electrode is greater in threshold voltage than the gate electrode.