Oxide Semiconductor Transistor Insulating Layer Oxygen Supply
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Solution Overview
Problem
Transistors using oxide semiconductors face reliability issues due to fluctuations in electric characteristics, particularly threshold voltage, caused by charge trapping and oxygen deficiency at the interface between insulating layers and the oxide semiconductor layer.
Innovation Solution
Incorporating a silicon peroxide radical into the insulating layers, such as the base and gate insulating layers, to reduce interface states and supply oxygen to the oxide semiconductor layer, thereby stabilizing the threshold voltage and improving reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If an oxide semiconductor layer is used in a transistor, then the transistor can operate at higher speed and be manufactured more easily compared to amorphous silicon or polycrystalline silicon transistors, but the transistor exhibits low reliability due to fluctuation in electric characteristics such as threshold voltage
Solution Approach 1:
The patent applies local quality by introducing a specific insulating layer structure with silicon peroxide radicals at the critical interface region between the insulating layer and oxide semiconductor layer. This localized modification targets the interface states and oxygen deficiency specifically at the interface, while the bulk oxide semiconductor layer maintains its high-speed operation characteristics. The silicon peroxide radical-containing layer is positioned precisely where needed to suppress charge trapping without affecting the overall device performance.
Solution Approach 2:
The patent employs composite materials by combining silicon oxide with silicon peroxide radicals to create a novel insulating layer structure. This composite insulating layer integrates the beneficial properties of silicon oxide (insulation) with silicon peroxide radicals (oxygen supply capability). The composite structure effectively addresses the reliability issue by suppressing charge trapping at the interface while maintaining the ease of manufacture and high-speed operation characteristics of oxide semiconductor transistors.
2Ease of manufacture
If conventional insulating layers are used in contact with oxide semiconductor layer, then the device structure is simple and easy to manufacture, but charge trapping occurs at the interface leading to threshold voltage fluctuation and reduced reliability
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition and electronic structure of the insulating layer. Specifically, silicon peroxide radicals are introduced into the silicon oxide insulating layer, changing its oxygen supply capability and interface state characteristics. This parameter change (adding silicon peroxide radicals) enables the insulating layer to actively suppress charge trapping at the interface, thereby improving reliability while maintaining ease of manufacture through existing semiconductor fabrication processes.
3Ease of manufacture
If oxygen deficiency exists in the oxide semiconductor layer, then the transistor can be manufactured with simpler processes, but oxygen deficiency acts as donors generating electrons which shifts threshold voltage in negative direction and reduces reliability
Solution Approach 1:
The patent applies preliminary action by pre-introducing silicon peroxide radicals into the insulating layer before the oxide semiconductor layer is formed or during subsequent processing. This preliminary preparation ensures that oxygen is readily available at the interface to compensate for oxygen deficiency in the oxide semiconductor layer. The silicon peroxide radicals act as a reservoir that can supply oxygen to suppress donor formation and prevent threshold voltage shift, thereby improving manufacturing precision while maintaining 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 use of silicon peroxide radicals in insulating layers effectively suppresses charge trapping and oxygen deficiency, leading to reduced off-state current, stable electrical characteristics, and enhanced reliability of oxide semiconductor transistors.
Implementation Method 1
supplying oxygen from the base insulating layer to the oxide semiconductor layer
Implementation Method 2
suppress trapping of a charge or the like, which can be generated due to the operation of a semiconductor device
Data Source
AI summary
Oxygen is released from the insulating layer, whereby oxygen deficiency in the oxide semiconductor layer and an interface state between the insulating layer and the oxide semiconductor layer can be reduced. Accordingly, a semiconductor device where reliability is high and variation in electric characteristics is small can be manufactured.