Oxide Semiconductor Transistor Oxygen Concentration Segmentation
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Solution Overview
Problem
It is challenging to manufacture transistors with oxide semiconductors that balance high field-effect mobility and large on-state current with low power consumption and high-speed operation, as existing devices either consume excessive power due to high mobility or operate slowly due to low mobility.
Innovation Solution
The solution involves forming separate transistors with different oxygen concentrations in the oxide semiconductor films, where one transistor has a higher oxygen concentration for low leakage current at negative gate voltage and another with lower oxygen concentration for high field-effect mobility and large on-state current, each optimized for specific circuit functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a transistor is designed with high field-effect mobility and large on-state current using oxide semiconductor, then the transistor can operate at high speed, but the transistor consumes a large amount of power due to high current at negative gate voltage
Solution Approach 1:
The invention divides the transistor population into two distinct segments: first transistors with high oxygen concentration optimized for low leakage current, and second transistors with low oxygen concentration optimized for high field-effect mobility and large on-state current. This segmentation allows each transistor type to be specialized for specific circuit functions, resolving the contradiction between high-speed operation and low power consumption by assigning high-mobility transistors to speed-critical paths and low-leakage transistors to power-critical regions.
Solution Approach 2:
The invention applies local quality by creating transistors with spatially varying oxygen concentrations within the oxide semiconductor film. First transistors have high oxygen concentration (5×10^19 to 5×10^21 atoms/cm³) in their channel-forming regions to minimize leakage, while second transistors have low oxygen concentration (<5×10^19 atoms/cm³) to maximize mobility. This local differentiation of material properties enables simultaneous optimization of both power efficiency and speed performance in different device locations.
2Use of energy by moving object
If a transistor is designed with low current at negative gate voltage to reduce power consumption, then the transistor consumes less power, but the transistor has low field-effect mobility and small on-state current causing slow operation
Solution Approach 1:
The invention segments transistor design into two specialized categories: first transistors with high oxygen concentration for low leakage current, and second transistors with low oxygen concentration for high field-effect mobility. This segmentation resolves the contradiction by allowing the system to use low-power transistors in power-critical circuits while using high-speed transistors in performance-critical circuits, achieving both low overall power consumption and high overall operation speed through architectural division.
Solution Approach 2:
The invention changes the oxygen concentration parameter of the oxide semiconductor film to create transistors with different electrical characteristics. By controlling oxygen concentration in the range of <5×10^19 to 5×10^21 atoms/cm³, the invention can tune the transistor's field-effect mobility and leakage current characteristics, enabling the selection of appropriate transistor types for different circuit requirements and thus resolving the speed-power tradeoff.
Data Source
AI summary
A semiconductor device which can operate at high speed and consumes a smaller amount of power is provided. In a semiconductor device including transistors each including an oxide semiconductor, the oxygen concentration of the oxide semiconductor film of the transistor having small current at negative gate voltage is different from that of the oxide semiconductor film of the transistor having high field-effect mobility and large on-state current. Typically, the oxygen concentration of the oxide semiconductor film of the transistor having high field-effect mobility and large on-state current is lower than that of the oxide semiconductor film of the transistor having small current at negative gate voltage.