Metal Oxide Transistor Mobility Enhancement via Oxygen Reduction
Solution Overview
Problem
Current metal oxide semiconductor transistors face challenges in achieving high carrier mobility due to complex manufacturing processes and poor uniformity of poly-silicon layers, with limited options for improving performance through material composition changes.
Innovation Solution
A metal oxide semiconductor transistor design featuring a mobility enhancing region with a reduced oxygen content, achieved by applying a mobility enhancing layer or medium that reacts with or bonds with oxygen in the metal oxide active layer, increasing carrier mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a poly-silicon layer is used as the active layer to improve carrier mobility, then carrier mobility increases, but manufacturing complexity increases and uniformity deteriorates
Solution Approach 1:
The patent changes the material composition parameter of the active layer from poly-silicon to metal oxide semiconductor, and further optimizes the oxygen content parameter within the metal oxide semiconductor to achieve high carrier mobility while maintaining manufacturing simplicity and uniformity
Solution Approach 2:
The patent creates a mobility enhancing region with different oxygen content compared to other regions of the active layer. This local variation in oxygen concentration (lower oxygen in the mobility enhancing region) optimizes carrier mobility in the critical transport region without affecting the entire layer uniformly
2Reliability
If a poly-silicon layer is used as the active layer to improve carrier mobility, then carrier mobility increases, but manufacturing uniformity deteriorates
Solution Approach 1:
The patent changes the material composition parameter from poly-silicon to metal oxide semiconductor, which inherently provides better deposition uniformity. The metal oxide semiconductor layer can be formed with consistent composition and properties across the entire wafer area, resolving the uniformity issue while maintaining high carrier mobility through oxygen content optimization
3Reliability
If oxygen content is reduced in the metal oxide active layer to increase carrier mobility, then carrier mobility increases, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies different oxygen content requirements to different regions of the active layer. The mobility enhancing region has lower oxygen content optimized for high carrier mobility, while other regions maintain standard oxygen content. This local differentiation allows optimization of the critical region without requiring extreme precision control across the entire layer
Solution Approach 2:
The patent forms the metal oxide semiconductor layer with controlled oxygen content during the deposition process, and then applies additional oxygen loss treatment (such as annealing or plasma treatment) to specifically reduce oxygen in the mobility enhancing region. This preliminary formation followed by selective modification achieves the desired oxygen distribution with manageable precision requirements
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 design enhances carrier mobility from 10 cm2V−1 s−1 to 80 cm2V−1 s−1, improving transistor performance while simplifying the manufacturing process and maintaining better uniformity.
Implementation Method 1
The material of the mobility enhancing layer includes a chemical composition capable of bonding with oxygen. Thus, the chemical composition capable of bonding with oxygen in the material of the mobility enhancing layer can react with the oxygen in the metal oxide compound of the metal oxide active layer.
Implementation Method 2
a portion of the oxygen in the metal oxide compound of the metal oxide active layer in the mobility enhancing region is lost
Data Source
AI summary
A metal oxide semiconductor transistor includes a gate, a metal oxide active layer, a gate insulating layer, a source, and a drain. The metal oxide active layer has a first surface and a second surface, and the first surface faces to the gate. The gate insulating layer is disposed between the gate and the metal oxide active layer. The source and the drain are respectively connected to the metal oxide active layer. The second surface defines a mobility enhancing region between the source and the drain. An oxygen content of the metal oxide active layer in the mobility enhancing region is less than an oxygen content of the metal oxide active layer in the region outside the mobility enhancing region. The metal oxide semiconductor transistor has high carrier mobility.