Dual-Oxygen Trench Gate Structure for GIDL and Threshold Control
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Solution Overview
Problem
Gate-Induced Drain Leakage (GIDL) characteristics significantly affect the performance of buried gate-type transistors, necessitating improved control of threshold voltage for high-performance operation.
Innovation Solution
A semiconductor device with a trench structure containing a first gate and a second gate, both made of oxygen-containing materials, where the oxygen content of the first gate is higher than that of the second gate, to enhance electrical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal gate electrodes are used to ensure high performance of transistors, then transistor performance is improved, but threshold voltage control becomes difficult due to GIDL characteristics
Solution Approach 1:
The gate electrode is divided into two distinct gates (first gate and second gate) with different oxygen contents. The first gate has higher oxygen content for stable threshold voltage control, while the second gate has lower oxygen content to minimize GIDL characteristics. This segmentation allows each gate to perform its specific function independently, resolving the contradiction between performance and controllability.
Solution Approach 2:
Different regions of the gate structure are assigned different oxygen concentrations to achieve different local properties. The first gate region contains more oxygen for threshold control, while the second gate region contains less oxygen for reduced GIDL. This local differentiation enables simultaneous optimization of both threshold voltage control and overall transistor performance.
2Ease of operation
If oxygen content in gate electrodes is increased to improve threshold voltage control, then threshold voltage control is improved, but device resistance increases
Solution Approach 1:
The gate electrode is segmented into two parts with different oxygen contents. The first gate has higher oxygen content optimized for threshold voltage control, while the second gate has lower oxygen content optimized for low resistance. This segmentation allows the device to achieve both good threshold control and low resistance simultaneously by distributing different functional requirements to different gate regions.
Solution Approach 2:
Different oxygen concentrations are applied to different parts of the gate structure to create locally optimized properties. The high-oxygen first gate provides excellent threshold control, while the low-oxygen second gate maintains low resistance. This local quality differentiation resolves the contradiction between threshold control and resistance.
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
The dual-gate structure with varying oxygen content improves threshold voltage control and reduces device resistance, enhancing the performance of buried gate-type transistors.
Implementation Method 1
each of the first gate and the second gate contains oxygen material, and an oxygen content of the first gate is greater than an oxygen content of the second gate
Implementation Method 2
substituting a surface of the second gate with silicon oxide by performing a heat treatment
Data Source
AI summary
A semiconductor device includes a trench formed in a substrate; a first gate filled in a lower portion of the trench; and a second gate disposed over the first gate, wherein each of the first gate and the second gate contains oxygen material, and an oxygen content of the first gate is greater than an oxygen content of the second gate.