In2O3-SnO2-ZnO Sputtering Target Composition for Stable Film Deposition
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The formation of oxide semiconductor thin films using the sputtering method often results in oxygen deficiency, abnormal discharge, and instability, leading to low mobility, high current leakage, and difficulties in achieving normally-off operation in thin film transistors (TFTs), particularly when using zinc oxide-based films.
Innovation Solution
A sputtering target comprising indium (In), tin (Sn), and zinc (Zn) with additional elements such as Mg, Si, Al, Sc, Ti, Y, Zr, Hf, Ta, La, or Sm, optimized in atomic ratios and crystal structure to reduce oxygen partial pressure requirements and prevent agglomerate formation, allowing for stable and efficient film deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a sputtering method is used to form an oxide semiconductor film containing zinc oxide, then the film can be formed efficiently, but oxygen deficiency occurs, abnormal discharge happens, and stable film formation cannot be attained
Solution Approach 1:
The invention changes the composition parameters of the sputtering target by adding specific elements (Ga, Ge, In, Sn, or Ta) to zinc oxide in controlled amounts. This compositional modification allows the film to be formed with adequate oxygen content without requiring high oxygen partial pressure during sputtering, thereby achieving both efficient film formation and stable, abnormal-discharge-free processing
Solution Approach 2:
The invention creates a composite oxide semiconductor material by combining zinc oxide with other metal oxides (Ga2O3, GeO2, In2O3, SnO2, or Ta2O5). This composite structure improves the material's inherent properties, making it more resistant to oxygen deficiency and abnormal discharge during sputtering while maintaining good TFT characteristics
2Reliability
If an oxide semiconductor film containing zinc oxide is used, then film formation can be conducted at high pressure, but the film deposition rate becomes low and heat treatment at high temperature is required
Solution Approach 1:
The invention modifies the target composition by adding specific metal oxides to zinc oxide, which changes the sputtering characteristics of the material. This allows film formation at lower pressures with higher deposition rates while still achieving good TFT performance, eliminating the need for high-temperature heat treatment
Solution Approach 2:
The invention replaces the need for expensive high-temperature processing equipment and long heat treatment cycles by using a chemically modified material that achieves desired properties through composition rather than extreme processing conditions, simplifying the manufacturing process
3Reliability
If gallium is added to the oxide semiconductor film, then TFT properties improve, but raw material cost increases due to gallium being a rare and expensive metal
Solution Approach 1:
The invention adjusts the compositional parameters by adding gallium oxide at very low concentrations (0.01-5 atomic%). This minimal addition is sufficient to improve TFT properties while keeping raw material costs acceptable. The invention also provides alternative compositions using cheaper elements like Ge, In, Sn, or Ta for those seeking cost reduction
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 enables the formation of oxide thin films with improved TFT properties, including enhanced mobility and reduced current leakage, without the need for increased oxygen partial pressure, thereby facilitating the production of high-performance thin film transistors.
Implementation Method 1
when a film is formed by a sputtering method, which is generally performed on the industrial basis
Data Source
AI summary
A sputtering target including indium (In), tin (Sn) and zinc (Zn) and an oxide including one or more elements X selected from the following group X,the atomic ratio of the elements satisfying the following formulas (1) to (4):Group X: Mg, Si, Al, Sc, Ti, Y, Zr, Hf, Ta, La, Nd, Sm0.10≦In/(In+Sn+Zn)≦0.85 (1)0.01≦Sn/(In+Sn+Zn)≦0.40 (2)0.10≦Zn/(In+Sn+Zn)≦0.70 (3)0.70≦In/(In+X)≦0.99 (4).