Semiconductor Device High-Temperature Stability
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Solution Overview
Problem
Transistors using oxide semiconductors exhibit higher off-state current and are more likely to have normally-on characteristics as temperature increases, leading to reduced reliability and fluctuations in electrical characteristics.
Innovation Solution
A semiconductor device with a metal oxide structure, including specific regions with controlled carrier concentrations and hydrogen concentration, is designed to stabilize operation at high temperatures, reduce off-state current, and enhance reliability by using a metal oxide with indium, aluminum, gallium, yttrium, or tin, and zinc, and incorporating tantalum nitride layers to manage carrier concentrations and hydrogen levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a transistor using an oxide semiconductor is used, then the off-state current is extremely low at room temperature, but the off-state current increases and normally-on characteristics occur at high temperatures
Solution Approach 1:
The patent applies local quality by creating distinct regions within the oxide semiconductor layer with different carrier concentrations. The first region (channel formation region) has a carrier concentration of 1×10^12 to 1×10^17 cm^-3, while the second region has a carrier concentration of 1×10^17 to 1×10^19 cm^-3. This spatial differentiation allows the channel region to maintain low off-state current at high temperatures while the other region provides necessary electrical characteristics.
Solution Approach 2:
The patent changes the carrier concentration parameter within the oxide semiconductor layer to resolve the temperature-dependent reliability issue. By controlling the carrier concentration to be 1×10^12 to 1×10^17 cm^-3 in the channel formation region, the transistor maintains stable electrical characteristics and low off-state current even at high temperatures, preventing normally-on characteristics.
2Power
If the carrier concentration in the oxide semiconductor is increased to improve conductivity, then the on-state current increases, but the off-state current also increases and normally-on characteristics occur
Solution Approach 1:
The patent applies local quality by creating distinct regions within the oxide semiconductor layer with different carrier concentrations. The first region (channel formation region) has a carrier concentration of 1×10^12 to 1×10^17 cm^-3, while the second region has a carrier concentration of 1×10^17 to 1×10^19 cm^-3. This spatial differentiation allows the channel region to maintain low off-state current at high temperatures while the other region provides necessary electrical characteristics.
Solution Approach 2:
The patent changes the carrier concentration parameter within the oxide semiconductor layer to resolve the temperature-dependent reliability issue. By controlling the carrier concentration to be 1×10^12 to 1×10^17 cm^-3 in the channel formation region, the transistor maintains stable electrical characteristics and low off-state current even at high temperatures, preventing normally-on characteristics.
Data Source
AI summary
A semiconductor device that stably operates even at high temperature is provided. The semiconductor device includes a metal oxide, an insulating layer, a first conductive layer, a second conductive layer, and a third conductive layer. The metal oxide includes a first region, a second region, and a third region. The first region overlaps with the first conductive layer. The second region overlaps with the second conductive layer. The third region overlaps with the third conductive layer with the insulating layer interposed therebetween. The value of the ratio of the carrier concentration in the first region to the carrier concentration in the third region is 100 or more. The value of the ratio of the carrier concentration in the second region to the carrier concentration in the third region is 100 or more.