TiN Gate Electrode Oxidation for FinFET Threshold Voltage Control
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Solution Overview
Problem
The increasing demand for high-performance, high-speed, and multi-functional semiconductor devices has led to the need for improved electrical characteristics in transistors, particularly in FinFETs, where the scaling down of planar metal oxide semiconductor FETs poses challenges in operating characteristics.
Innovation Solution
A semiconductor device with multiple transistors having different gate electrode structures, including conductive layers of TiN and TiON, which allow for varying threshold voltages by oxidizing TiN layers to form TiON, enhancing electrical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If planar metal oxide semiconductor FETs are scaled down to increase integration density, then device density increases, but operating characteristics deteriorate
Solution Approach 1:
The patent transitions from planar 2D channel structure to 3D FinFET structure by introducing vertical fins that extend from the substrate. This dimensional change increases the effective channel area and improves gate control without further scaling the planar dimensions, thereby maintaining operating characteristics while increasing integration density.
Solution Approach 2:
The gate electrode structure uses composite materials including TiN, TiON, and other conductive layers with different properties. The TiN layer provides high conductivity, while TiON layers with varying oxygen concentrations allow precise threshold voltage control, enabling optimized performance in high-density FinFET structures.
2Adaptability or versatility
If multiple transistor types with different threshold voltages are created, then device functionality increases, but manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by forming TiON layers with different oxygen concentrations in specific regions to create transistors with different threshold voltages. By controlling the oxidation degree of TiN layers locally, the patent achieves diverse transistor characteristics (different Vth) within the same manufacturing process, enabling enhanced device functionality without proportionally increasing manufacturing complexity.
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 use of TiN and TiON layers in the gate electrodes of the semiconductor device improves transistor performance by adjusting threshold voltages, resulting in improved electrical characteristics and manufacturing efficiency.
Implementation Method 1
one or a plurality of layers is formed of TiON formed by oxidizing TiN
Data Source
AI summary
A semiconductor memory device includes a substrate having a first region and a second region. A first gate electrode layer is on the first region and includes a first conductive layer including a first plurality of layers, and includes a first upper conductive layer on the first conductive layer. A second gate electrode layer is on the second region and includes a second conductive layer including a second plurality of layers, and includes a second upper conductive layer on the second conductive layer. At least one of the first plurality of layers includes titanium oxynitride (TiON). A first transistor including the first gate electrode layer and a second transistor including the second gate electrode layer are metal oxide semiconductor field effect transistors (MOSFETs) having the same channel conductivity type, and a threshold voltage of the first transistor is smaller than a threshold voltage of the second transistor.