Oxide Semiconductor Surface Roughness Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The surface roughness of oxide semiconductor layers, typically formed by sputtering, leads to high interface roughness with gate insulation layers, causing reliability issues such as breakdown electric field and time-dependent dielectric breakdown in semiconductor devices.
Innovation Solution
A flattening process, such as plasma treatment using a xenon and hydrogen gas mixture, is applied to the oxide semiconductor layer before forming the gate insulation layer to reduce surface roughness to less than 2 nm, thereby improving interface smoothness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a sputtering process is used to form the oxide semiconductor layer, then the oxide semiconductor layer can be formed efficiently, but the surface roughness of the oxide semiconductor layer becomes large
Solution Approach 1:
A flattening process is performed on the oxide semiconductor layer before forming the gate insulation layer to reduce surface roughness. This preliminary action addresses the roughness issue created by sputtering before subsequent processing steps, ensuring a smooth interface for the gate insulation layer while maintaining the efficiency of the sputtering formation process.
2Productivity
If the oxide semiconductor layer is formed by sputtering, then the layer can be deposited quickly, but the interface roughness between the oxide semiconductor layer and gate insulation layer increases
Solution Approach 1:
The flattening process is applied to the oxide semiconductor layer before depositing the gate insulation layer. This preliminary flattening action ensures that the interface between the oxide semiconductor layer and gate insulation layer has reduced roughness, improving device reliability while maintaining the high deposition speed advantage of the sputtering process.
3Reliability
If the surface roughness of the oxide semiconductor layer is reduced by a flattening process, then the interface roughness with the gate insulation layer is improved, but an additional process step is required
Solution Approach 1:
The flattening process is integrated into the existing manufacturing sequence by positioning it between the oxide semiconductor layer formation and the gate insulation layer formation. This merging approach incorporates the roughness reduction step into the overall process flow without requiring separate dedicated equipment or operations, thereby improving interface quality while minimizing the increase in device 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 flattening process enhances the reliability of oxide semiconductor devices by reducing surface and interface roughness, improving breakdown electric field and time-dependent dielectric breakdown performance.
Implementation Method 1
A flattening process, such as plasma treatment using a xenon and hydrogen gas mixture, is applied to the oxide semiconductor layer before forming the gate insulation layer to reduce surface roughness to less than 2 nm
Data Source
AI summary
A manufacturing method of an oxide semiconductor device includes the following steps. A first oxide semiconductor layer is formed on a substrate. A gate insulation layer is formed on the first oxide semiconductor layer. A first flattening process is performed on a top surface of the first oxide semiconductor layer before the step of forming the gate insulation layer. A roughness of the top surface of the first oxide semiconductor layer after the first flattening process is smaller than the roughness of the top surface of the first oxide semiconductor layer before the first flattening process.