Oxide Semiconductor Transistor Hydrogen Supply
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Solution Overview
Problem
Transistors manufactured using conventional oxide semiconductors face limitations in field-effect mobility and are not suitable for large-sized display devices, particularly when used as switching elements in driver circuits.
Innovation Solution
The formation of an oxide semiconductor layer with improved characteristics is achieved by stacking an insulating layer containing hydrogen, which supplies hydrogen to the interface between the gate insulating layer and the oxide semiconductor layer, and performing heat treatment to oxidize oxygen vacancies, resulting in an intrinsic-type oxide semiconductor layer with enhanced properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a transistor is manufactured using conventional oxide semiconductor, then the manufacturing process is simpler and can be applied to large glass substrates, but the field-effect mobility is limited (10-20 cm²/Vs) and insufficient for high-performance applications
Solution Approach 1:
The patent applies preliminary action by forming an insulating layer containing hydrogen (such as silicon nitride or aluminum nitride) before forming the oxide semiconductor layer. This pre-prepared hydrogen source will later supply hydrogen to the oxide semiconductor layer during heat treatment, improving field-effect mobility without complicating the overall manufacturing process. The hydrogen supply mechanism is established in advance through the insulating layer structure.
Solution Approach 2:
The patent changes physical and chemical parameters by controlling the hydrogen concentration in the oxide semiconductor layer through heat treatment. By heating the device at temperatures between 200-450°C, hydrogen is supplied from the insulating layer to the oxide semiconductor layer, transforming it from a low-mobility state to a high-mobility state. This parameter change (hydrogen concentration) directly improves field-effect mobility while maintaining manufacturing simplicity.
2Manufacturing precision
If the oxide semiconductor layer is treated to improve field-effect mobility through hydrogen supply, then on-state current and field-effect mobility increase, but off-state current may increase due to hydrogen-related defects
Solution Approach 1:
The patent applies local quality by selectively supplying hydrogen to specific regions of the oxide semiconductor layer through the insulating layer. The hydrogen supply is localized to the interface region between the insulating layer and oxide semiconductor layer, where it most effectively improves field-effect mobility. This localized treatment avoids excessive hydrogen incorporation in the bulk material that would cause defects and increase off-state current.
Solution Approach 2:
The patent uses composite material structure by combining the oxide semiconductor layer with an insulating layer containing hydrogen (such as silicon nitride or aluminum nitride). This composite structure allows controlled hydrogen supply to the oxide semiconductor layer while the insulating layer acts as a barrier to prevent excessive hydrogen diffusion. The combination achieves high field-effect mobility while maintaining low off-state current through the synergistic effect of the two materials.
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 approach significantly increases the on-state current and field-effect mobility of transistors, reducing off-state current and improving the on/off ratio, enabling the use of high-performance semiconductor devices in large-sized display applications.
Implementation Method 1
hydrogen in the insulating layer including hydrogen is supplied to at least one of an interface between a gate insulating layer and the oxide semiconductor layer, the oxide semiconductor layer, and the interface between the oxide semiconductor layer and the insulating layer
Implementation Method 2
performing heat treatment so that hydrogen in the insulating layer including hydrogen is supplied to at least the oxide semiconductor layer
Data Source
AI summary
A manufacturing method of a semiconductor device, which includes the steps of forming a gate electrode layer over a substrate having an insulating surface, forming a gate insulating layer over the gate electrode layer, forming an oxide semiconductor layer over the gate insulating layer, forming a source electrode layer and a drain electrode layer over the oxide semiconductor layer, forming an insulating layer including oxygen over the oxide semiconductor layer, the source electrode layer, and the drain electrode layer, and after formation of an insulating layer including hydrogen over the insulating layer including oxygen, performing heat treatment so that hydrogen in the insulating layer including hydrogen is supplied to at least the oxide semiconductor layer.