Oxide Semiconductor Transistor Structure With Aluminum Gradient Stability
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Solution Overview
Problem
Current semiconductor devices face challenges in achieving small variations in transistor electrical characteristics, reliability, high on-state current, miniaturization, high integration, and low power consumption while maintaining stable electrical properties.
Innovation Solution
A semiconductor device structure incorporating an oxide with indium, gallium, aluminum, and zinc, along with specific conductor and insulator layers, including a concentration gradient in the aluminum concentration and amorphous insulators, to enhance electrical characteristics and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional semiconductor devices are used, then manufacturing and operation are straightforward, but electrical characteristics show large variations and reliability is poor
Solution Approach 1:
The patent applies parameter changes by introducing a concentration gradient of aluminum in the oxide semiconductor layer. The aluminum concentration varies from 0 atomic% at the interface with the gate insulator to 5 atomic% at the top surface, which modifies the electrical characteristics to achieve both low threshold voltage and low off-state current, reducing variation in transistor characteristics
Solution Approach 2:
The patent implements local quality by creating different aluminum concentrations at different depths within the oxide semiconductor layer. The region near the gate insulator has 0 atomic% aluminum while the top surface has 5 atomic%, allowing different regions to fulfill different functional requirements for optimal electrical performance
2Productivity
If device size is reduced for miniaturization, then integration density increases, but maintaining stable electrical properties becomes difficult
Solution Approach 1:
The concentration gradient structure allows the transistor to maintain stable electrical characteristics even when miniaturized. The gradient profile (0 atomic% at interface to 5 atomic% at surface) ensures consistent electrical properties across different device sizes, enabling high integration density without sacrificing reliability
3Use of energy by moving object
If power consumption is reduced, then energy efficiency improves, but on-state current and switching performance may deteriorate
Solution Approach 1:
The patent resolves this contradiction by optimizing the aluminum concentration gradient in the oxide semiconductor. The specific profile (0 atomic% at gate insulator interface increasing to 5 atomic% at top surface) achieves both low off-state current (reducing power consumption) and adequate on-state current (maintaining switching performance)
Data Source
AI summary
A semiconductor device with a small variation in transistor electrical characteristics is provided. The semiconductor device includes an oxide; a first conductor, a second conductor, and a first insulator over the oxide; a second insulator over the first conductor and the second conductor; a third insulator over the first insulator; a third conductor over the third insulator; and a fourth insulator over the second insulator and the third conductor. The fourth insulator is in contact with a top surface of the second insulator and a top surface of the third conductor. The first insulator includes regions that are in contact with a top surface of the oxide, a side surface of the first conductor, a side surface of the second conductor, and a side surface of the second insulator. The oxide includes indium, gallium, aluminum, and zinc. Each of the first insulator and the fourth insulator includes aluminum and oxygen. The fourth insulator has an amorphous structure. The oxide has a concentration gradient in which an aluminum concentration increases toward the top surface of the oxide from the bottom surface of the oxide.