Oxide Transistor Contact Structure for Higher On-State Current
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Solution Overview
Problem
Transistors in semiconductor devices often exhibit low on-state current due to high contact resistance between the semiconductor layer and the source or drain electrodes, leading to reduced operation speed and increased area occupation, which affects the performance of display devices.
Innovation Solution
The semiconductor device incorporates a specific layered structure with insulating and conductive layers, including a metal oxide layer in contact with hydrogen-containing insulating layers, which reduces contact resistance through oxygen vacancy formation and enhances electrical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the contact resistance between the semiconductor layer and source/drain electrodes is reduced, then the on-state current increases, but the device structure becomes more complex
Solution Approach 1:
A metal oxide layer is introduced as an intermediary between the semiconductor layer and the source/drain electrodes. This metal oxide layer contains oxygen vacancies that act as donor states, reducing contact resistance by providing additional charge carriers at the interface. The metal oxide layer serves as a mediator that improves electrical contact without requiring changes to the semiconductor material itself.
Solution Approach 2:
The patent changes the chemical composition and physical properties of the interface layer by using a metal oxide with controlled oxygen vacancies. By adjusting the metal oxide layer's composition (e.g., In-Ga-Zn-O system) and controlling the formation of oxygen vacancies through fabrication processes, the contact resistance is modified to achieve lower resistance while maintaining a manageable device structure.
2Area of stationary object
If the transistor size is reduced, then the device occupies less area, but the on-state current decreases due to higher contact resistance
Solution Approach 1:
The metal oxide layer acts as an intermediary that specifically addresses the contact resistance issue in miniaturized transistors. By placing this layer at the critical interface between the semiconductor channel and source/drain electrodes, the patent reduces contact resistance without increasing the overall transistor footprint, thus maintaining high on-state current in compact devices.
Solution Approach 2:
The patent applies local quality by introducing the metal oxide layer specifically at the contact interfaces where it is most needed to reduce resistance, rather than modifying the entire transistor structure. This localized approach allows area reduction while maintaining high current flow at the critical contact regions.
3Speed
If the channel length is reduced, then the operation speed increases, but the contact resistance becomes more significant
Solution Approach 1:
In short-channel transistors where contact resistance has a proportionally larger impact, the metal oxide layer serves as a mediator that compensates for this effect. The oxygen vacancies in the metal oxide layer provide additional charge carriers that reduce contact resistance, thereby maintaining high operation speed despite the reduced channel length.
Solution Approach 2:
The patent changes the electrical parameters at the contact interface by introducing the metal oxide layer with controlled oxygen vacancy concentration. This modifies the contact resistance parameter to be less significant relative to the reduced channel length, thereby maintaining high-speed operation in miniaturized transistors.
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 results in transistors with higher on-state current, smaller size, and improved reliability, enabling high-speed operation with reduced power consumption and area occupation, suitable for high-resolution display devices.
Implementation Method 1
the metal oxide layer includes a region positioned in the first opening and being in contact with the first conductive layer; the first insulating layer includes hydrogen
Data Source
AI summary
A semiconductor device is provided over a base insulating layer including hydrogen. A first conductive layer, a spacer, and a second conductive layer are provided over the base insulating layer. The spacer and the second conductive layer comprise an opening reaching the first conductive layer in which a metal oxide layer is provided. The metal oxide layer includes a region in contact with the first conductive layer and the second conductive layer. The first conductive layer and the second conductive layer function as one and the other of a source electrode and a drain electrode of the transistor. A gate insulating layer is provided over the metal oxide layer to include a region positioned in the opening. A gate electrode is provided to include a region facing the metal oxide layer with the gate insulating layer between the region and the metal oxide layer in the opening.