Oxide Semiconductor Transistor Dual-Layer Electrode Oxygen Supply
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Solution Overview
Problem
In transistors with oxide semiconductor layers, the insufficient supply of oxygen from the oxide insulating layer to the semiconductor layer due to contact with source and drain electrode layers leads to issues like negative threshold voltage shifts, particularly in devices with short channel lengths, affecting electric characteristics and reliability.
Innovation Solution
The design includes a semiconductor device with a specific structure featuring a first insulating layer, a second insulating layer, an oxide semiconductor layer, and conductive layers, where the oxide semiconductor layer is in contact with the first insulating layer, and the conductive layers are electrically connected to the oxide semiconductor layer, with the second insulating layer acting as a gate insulating film. This structure ensures oxygen supply to the oxide semiconductor layer, reducing oxygen loss and improving transistor performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the transistor channel length is reduced for miniaturization, then the integration density is improved, but the threshold voltage becomes unstable
Solution Approach 1:
The electrode is divided into two functional layers that can be independently optimized. The first conductive layer ensures proper electrical connection with the oxide semiconductor layer, while the second conductive layer protects against oxygen loss, thereby stabilizing threshold voltage even in miniaturized transistors with short channel lengths.
Solution Approach 2:
By changing the structural parameters of the electrode from a single layer to a two-layer configuration, the patent achieves both miniaturization capability and threshold voltage stability. The dual-layer structure allows for optimized thickness and material composition of each layer to meet conflicting requirements.
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
This configuration enhances the electric characteristics and reliability of the transistor by maintaining oxygen supply to the oxide semiconductor layer, reducing negative threshold voltage shifts, and increasing on-state current, making it suitable for miniaturization and high integration.
Implementation Method 1
When an oxide insulating layer is used as a base insulating film, for example, a channel formation region, which is changed to an n-type region by oxygen vacancies or the like, in the oxide semiconductor layer can be supplied with oxygen
Data Source
AI summary
A semiconductor device having favorable electric characteristics is provided. An oxide semiconductor layer includes first and second regions apart from each other, a third region which is between the first and second regions and overlaps with a gate electrode layer with a gate insulating film provided therebetween, a fourth region between the first and third regions, and a fifth region between the second and third regions. A source electrode layer includes first and second conductive layers. A drain electrode layer includes third and fourth conductive layers. The first conductive layer is formed only over the first region. The second conductive layer is in contact with an insulating layer, the first conductive layer, and the first region. The third conductive layer is formed only over the second region. The fourth conductive layer is in contact with the insulating layer, the third conductive layer, and the second region.