Oxide Semiconductor Transistor Sidewall Oxidation for Low Off-State Current
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Solution Overview
Problem
Conventional oxide semiconductor transistors lack sufficient characteristics for practical use, particularly in terms of subthreshold swing, on/off ratio, and reliability.
Innovation Solution
A semiconductor device with an oxide semiconductor layer, source and drain electrodes having oxidized side surfaces formed by plasma treatment with a high frequency power of 300 MHz to 300 GHz and a mixed gas of oxygen and argon, and a gate insulating layer covering these electrodes, along with a gate electrode, to improve transistor characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional oxide semiconductor transistors are used, then manufacturing is simpler, but transistor characteristics (subthreshold swing, on/off ratio, reliability) are insufficient
Solution Approach 1:
The patent applies local quality by forming an oxide region specifically on the side surface of the source or drain electrode that contacts the oxide semiconductor layer. This localized oxidation treatment targets only the critical interface area, improving transistor characteristics (subthreshold swing, on/off ratio, reliability) without requiring complex modifications to the entire device structure. The oxide region is formed by plasma treatment with oxygen and argon mixed gas, creating a localized improvement at the electrode-semiconductor interface.
2Reliability
If plasma treatment with high frequency power and mixed gas is applied, then transistor reliability improves, but manufacturing process complexity increases
Solution Approach 1:
The patent employs parameter changes by optimizing plasma treatment conditions including high frequency power (300 MHz to 300 GHz), mixed gas composition (oxygen and argon), pressure, and treatment time. These parameter optimizations enable effective formation of the oxide region while maintaining process simplicity. The specific parameter range achieves reliable oxide region formation without requiring excessively complex manufacturing procedures, balancing reliability improvement with ease of manufacture.
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 solution significantly enhances the subthreshold swing, on/off ratio, and reliability of the transistor, achieving an off-state current of 1×10−13 A or less and a hydrogen concentration of 5×1019/cm3 or less in the oxide semiconductor layer.
Implementation Method 1
a source electrode and a drain electrode with an oxidized side surface formed by plasma treatment with a high frequency power of 300 MHz to 300 GHz and a mixed gas of oxygen and argon
Implementation Method 2
the source electrode and the drain electrode have an oxide region formed by oxidizing a side surface thereof
Data Source
AI summary
A semiconductor device includes an oxide semiconductor layer, a source electrode and a drain electrode electrically connected to the oxide semiconductor layer, a gate insulating layer covering the oxide semiconductor layer, the source electrode, and the drain electrode, and a gate electrode over the gate insulating layer. The source electrode and the drain electrode include an oxide region formed by oxidizing a side surface thereof. Note that the oxide region of the source electrode and the drain electrode is preferably formed by plasma treatment with a high frequency power of 300 MHz to 300 GHz and a mixed gas of oxygen and argon.