Tin-Based Oxide Thin Film Transistor Channel Layer
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Solution Overview
Problem
P-type oxide thin film transistors have limited performance due to large hole effective mass and poor carrier transport characteristics, which is not adequately addressed by existing technologies.
Innovation Solution
A thin film transistor with a channel layer made of tin-based oxide (SnMO) containing non-metal chalcogen or halogen elements, such as selenium, is used, where the composition (SnMxO1-x) is optimized to reduce hole effective mass and surface roughness, and may include metal elements or P-type impurities to enhance electrical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a P-type oxide semiconductor is used as a channel layer, then the thin film transistor can be fabricated, but the hole effective mass is large and carrier transport characteristics are poor
Solution Approach 1:
The patent changes the chemical composition parameters of the oxide semiconductor by introducing non-metal elements (S, Se, Te) and metal elements (Ga, In, Zn) to form composite oxide semiconductors. This compositional parameter change reduces the hole effective mass from conventional values to ranges of 0.1-0.5 m0, thereby improving carrier transport characteristics while maintaining P-type conductivity
Solution Approach 2:
The patent uses composite oxide semiconductor materials combining multiple elements (e.g., In-Ga-Zn-O-S, In-Ga-Zn-O-Se, In-Ga-Zn-O-S-Te) to achieve superior electrical properties. The composite structure allows optimization of band structure and carrier mobility, resolving the contradiction between achieving functional operation and maintaining poor transport characteristics
2Manufacturing precision
If conventional oxide semiconductors are used, then fabrication is simple, but surface roughness of the channel layer is poor
Solution Approach 1:
The patent optimizes deposition parameters including oxygen partial pressure (0.1-100 mTorr), substrate temperature (100-500°C), and power ratios during sputtering to control surface morphology. These parameter changes achieve surface roughness reduction to Ra < 0.5 nm while incorporating multiple elements into the channel layer
Solution Approach 2:
The patent uses oxygen as an intermediary element during the sputtering process to control the oxidation state and surface morphology of the composite oxide semiconductor. Oxygen partial pressure control acts as a mediator to achieve smooth surfaces while maintaining the desired stoichiometry of multi-element oxides
Data Source
AI summary
Provided is a thin film transistor including a source electrode, a drain electrode, and a channel layer connecting the source electrode and the drain electrode. The channel layer includes a tin-based oxide represented by SnMO, wherein M includes at least one of a non-metal chalcogen element or a halogen element.