Transistor Hole Blocking Layer Oxynitride Channel
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Solution Overview
Problem
Transistors with oxynitride semiconductor channel layers face issues with high hole conduction and low sub-threshold slope, leading to increased off-current and reduced performance in display devices.
Innovation Solution
Incorporating a hole blocking layer with a lower valence band maximum energy level than the channel layer, made of materials like GaZn oxide, between the channel layer and source/drain electrodes, to suppress hole conduction and enhance sub-threshold slope, while allowing electron tunneling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an oxynitride semiconductor channel layer is used to improve carrier mobility, then operational characteristics are improved, but hole conduction increases leading to high off-current
Solution Approach 1:
A hole blocking layer is introduced as an intermediary between the oxynitride semiconductor channel layer and the source/drain electrodes. This intermediate layer selectively blocks hole conduction while allowing electron transport, thereby reducing off-current without compromising the high carrier mobility advantage of the oxynitride channel layer.
Solution Approach 2:
The hole blocking layer is applied locally at specific interfaces (channel layer-source electrode and channel layer-drain electrode interfaces) rather than throughout the entire device. This localized application targets the specific problem of hole injection from electrodes into the channel, while preserving the overall electrical characteristics of the transistor.
2Reliability
If an oxynitride semiconductor channel layer is used to improve carrier mobility, then operational characteristics are improved, but sub-threshold slope decreases
Solution Approach 1:
The hole blocking layer acts as a mediator that modifies the energy band alignment at the channel-electrode interfaces. By creating appropriate energy barriers, it improves the sub-threshold slope characteristic while maintaining the benefits of the oxynitride channel layer for high carrier mobility operation.
3Object-generated harmful factors
If a hole blocking layer is added to reduce off-current, then hole conduction is suppressed, but device complexity increases
Solution Approach 1:
The hole blocking layer is implemented only where needed - at the critical interfaces between the channel layer and source/drain electrodes - rather than as a comprehensive structural modification throughout the device. This localized approach minimizes the increase in device complexity while effectively addressing the off-current problem.
Solution Approach 2:
The transistor structure becomes a composite system combining the oxynitride semiconductor channel layer with the hole blocking layer. This composite structure leverages the complementary properties of each material: the high carrier mobility of oxynitride and the hole-blocking capability of the interface layer, achieving improved performance without proportionally increasing 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 solution effectively reduces off-current and increases the sub-threshold slope, improving the overall performance and reliability of transistors in display devices by controlling hole flow and maintaining low leakage currents.
Implementation Method 1
a hole blocking layer, and source and drain electrodes. The hole blocking layer has a lower valence band maximum energy level than a valance band maximum energy level of the channel layer
Implementation Method 2
A conduction band minimum energy level of the hole blocking layer may be higher than a conduction band minimum energy level of the channel layer, and the hole blocking layer may have a thickness configured to allow tunneling of electrons
Data Source
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AI summary
A transistor may include a hole blocking layer between a channel layer including oxynitride and an electrode electrically connected to the channel layer. The hole blocking layer may be disposed in a region between the channel layer and at least one of a source electrode and a drain electrode. The channel layer may include, for example, zinc oxynitride (ZnON). A valence band maximum energy level of the hole blocking layer may be lower than a valence band maximum energy level of the channel layer.