Thin Film Transistor ALD Oxide Interface
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Solution Overview
Problem
The contact resistance between the active layer and source/drain electrodes in thin film transistors is high due to poor interface characteristics, affecting the electrical characteristics of thin film transistors and organic light emitting display apparatus.
Innovation Solution
The active layer and source/drain electrodes are formed using an atomic layer deposition (ALD) and in-situ process with a Zn-based oxide, ensuring a smooth interface with a root mean square (RMS) surface roughness less than 1 nm, and controlled carrier concentrations to reduce contact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the active layer and source/drain electrodes are formed as thin films, then the device structure is achieved, but the contact resistance increases due to poor interface characteristics
Solution Approach 1:
The patent applies parameter changes by controlling the surface roughness of the active layer to be less than 1 nm RMS through precise deposition process parameters. This involves adjusting deposition conditions such as temperature, pressure, and material flow rates to achieve the required surface smoothness, thereby reducing contact resistance while maintaining the thin film structure.
Solution Approach 2:
The patent uses composite materials by forming the active layer and source/drain electrodes from oxidized materials (such as zinc oxide) that can be deposited in an oxidizing atmosphere. This composite approach allows for better interface characteristics and reduced contact resistance compared to traditional metal-semiconductor interfaces, while maintaining the thin film configuration.
2Ease of manufacture
If conventional deposition methods are used, then the manufacturing process is simpler, but the surface roughness exceeds 1 nm and contact resistance increases
Solution Approach 1:
The patent changes the deposition parameters by using atomic layer deposition (ALD) with specific temperature control and oxidizing atmosphere conditions. This method achieves surface roughness less than 1 nm RMS while maintaining a relatively simple sequential deposition process, resolving the contradiction between manufacturing simplicity and surface precision.
Solution Approach 2:
The patent replaces conventional physical vapor deposition methods with chemical vapor deposition through ALD. This substitution allows for precise control of film formation at the atomic level, achieving the required surface smoothness through chemical reactions rather than physical deposition mechanisms, thereby maintaining ease of manufacture while improving precision.
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 improves the electrical characteristics of the thin film transistor by reducing contact resistance and enhancing the interface properties between the active layer and source/drain electrodes.
Implementation Method 1
the active layer and the source an drain electrodes being formed using an atomic layer deposition (ALD) and an insitu process
Implementation Method 2
a root mean square (RMS) value of surface roughness of the active layer which contacts the source and drain electrodes being less than 1 nm
Data Source
AI summary
A thin film transistor includes a gate electrode; an active layer formed of an oxide and insulated from the gate electrode; and a source electrode and a drain electrode formed of an oxide on the active layer such that the source electrode and the drain electrode are insulated from the gate electrode and electrically connected to the active layer, wherein the active layer, the source and the drain electrode are formed using an atomic layer deposition (ALD) and an insitu process, and a root mean square (RMS) value of the surface roughness of the active layer which contacts with the source and drain electrodes is less than 1 nm in order to reduce the contact resistance between the active layer and the source and drain electrodes, a method of manufacturing the same, an organic light emitting display apparatus including the thin film transistor, and a method of manufacturing the same.