Oxide Transistor Channel Composition Gradient for Photosensitivity
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Solution Overview
Problem
Transistors with oxide channel layers are photosensitive, leading to changes in their characteristics when exposed to light, which affects their performance in electronic devices such as flat panel displays.
Innovation Solution
A transistor design featuring a channel layer composed of indium (In), zinc (Zn), and a metal element like hafnium (Hf), with varying compositions in a multi-layered structure, where the amount of the metal element increases towards the gate, and indium decreases, to suppress light-induced changes in characteristics while maintaining high mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an oxide layer is used as a channel layer to enhance carrier mobility, then the operating characteristics of the transistor are improved, but the transistor becomes photosensitive and its characteristics are easily changed by light
Solution Approach 1:
The patent changes the compositional parameters of the oxide channel layer by incorporating multiple metal elements (In, Zn, and a first element) in specific proportions. By adjusting the concentration ratios of these elements, the patent achieves high carrier mobility while reducing photosensitivity, as evidenced by the gradient structure where composition varies through the layer thickness
Solution Approach 2:
The patent creates a composite oxide material system containing multiple metal elements (In, Zn, and at least one first element from Hf, Y, Ta, Zr, Ga, or Al). This composite structure combines the high mobility benefits of In-containing oxides with the photosensitivity suppression benefits of specific first elements, achieving both improved operating characteristics and reduced light-induced changes
2Object-affected harmful factors
If the amount of metal element increases towards the gate to suppress photosensitivity, then light-induced changes are reduced, but the composition becomes non-uniform
Solution Approach 1:
The patent applies local quality by creating a gradient composition structure where the concentration of metal elements varies through the thickness of the channel layer. Specifically, the amount of the first element increases towards the gate while In and Zn decrease, with different composition ratios in different regions. This local compositional variation suppresses photosensitivity near the gate while maintaining overall layer integrity
Data Source
AI summary
Transistors, electronic devices including a transistor and methods of manufacturing the same are provided, the transistor includes an oxide semiconductor layer (as a channel layer) having compositions that vary in one direction. The channel layer may be an oxide layer including a first element, a second element, and Zn, which are metal elements. The amount of at least one of the first element, the second element, and Zn may change in a deposition direction of the channel layer. The first element may be any one of hafnium (Hf), yttrium (Y), tantalum (Ta), zirconium (Zr), gallium (Ga), aluminum (Al) or combinations thereof. The second element may be indium (In). The channel layer may have a multi-layered structure including at least two layers with different compositions.