IGZO Semiconductor Device with Oxygen Barrier Layer
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Solution Overview
Problem
Current semiconductor devices face challenges in achieving high reliability, favorable electrical characteristics, high on-state current, miniaturization, high integration, long data retention, high-speed data writing, low power consumption, and design flexibility, particularly in using oxide semiconductors like In—Ga—Zn oxide (IGZO) which struggle with impurity diffusion and crystallinity issues.
Innovation Solution
A semiconductor device structure incorporating multiple oxide layers and conductors with specific insulators to inhibit oxygen and hydrogen diffusion, using a sputtering method for oxide deposition, and a cleaning process with diluted ammonia water to reduce impurity concentration, ensuring a c-axis aligned crystal structure and low defect states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oxide semiconductors like IGZO are used for transistors, then low off-state current and favorable electrical characteristics are achieved, but impurity diffusion and crystallinity issues reduce reliability
Solution Approach 1:
A barrier layer comprising aluminum oxide or aluminum nitride is introduced between the oxide semiconductor layer and adjacent layers. This intermediary barrier layer effectively prevents impurity diffusion into the oxide semiconductor, thereby improving device reliability without affecting the favorable electrical characteristics of IGZO transistors
Solution Approach 2:
The patent employs a composite structure combining oxide semiconductor materials (In-Ga-Zn oxide) with barrier materials (aluminum oxide, aluminum nitride) to create a multi-layer configuration that leverages the low off-state current properties of IGZO while simultaneously blocking impurity diffusion through the integrated barrier layer
2Reliability
If aluminum is added to In-Ga-Zn oxide to improve electrical characteristics, then on-state current increases, but aluminum diffusion creates defect states
Solution Approach 1:
The barrier layer of aluminum oxide or aluminum nitride serves as a mediator that allows controlled aluminum presence in the oxide semiconductor for improved electrical characteristics while preventing excessive aluminum diffusion that would create harmful defect states in the channel formation region
Solution Approach 2:
The patent applies different aluminum concentrations in different regions: aluminum is present in the oxide semiconductor layer to enhance electrical characteristics, while the barrier layer selectively blocks aluminum diffusion into regions where it would create defect states, achieving local optimization of material properties
3Reliability
If oxide semiconductor layers are deposited using sputtering method, then favorable crystallinity and c-axis alignment are achieved, but manufacturing complexity increases
Solution Approach 1:
The patent utilizes sputtering method parameters (gas flow ratios, power density, substrate temperature) to achieve favorable crystallinity and c-axis alignment of the oxide semiconductor. By optimizing these parameters, the patent achieves high reliability through improved crystallinity while managing manufacturing complexity through controlled process parameters
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
The solution provides a highly reliable semiconductor device with improved electrical characteristics, increased on-state current, high frequency performance, and reduced power consumption, while maintaining stability and reliability by minimizing impurity diffusion and enhancing crystallinity.
Implementation Method 1
a sputtering method for oxide deposition
Implementation Method 2
The first insulator has a function of inhibiting diffusion of oxygen
Implementation Method 3
a cleaning process with diluted ammonia water to reduce impurity concentration
Data Source
AI summary
A semiconductor device with favorable reliability is provided. The semiconductor device includes a first oxide, a second oxide, a first conductor, a second conductor, a third conductor, a first insulator, and a second insulator. The first conductor is provided in contact with a top surface of the first oxide. The second conductor is provided in contact with the top surface of the first oxide. The first insulator is provided over the first conductor and the second conductor. The second oxide is provided in contact with the top surface of the first oxide. The second insulator is provided over the second oxide. The third conductor is provided over the second insulator. The first insulator has a function of inhibiting diffusion of oxygen. The first oxide includes indium, an element M (M is gallium, yttrium, or tin), and zinc. The first oxide includes a first region overlapping with the third conductor. A region of the first region in contact with the second oxide includes a region in which an atomic ratio of aluminum (Al) to the element M is less than 0.1.