Oxide Semiconductor Target Impurity Compensation
Solution Overview
Problem
The manufacturing of oxide semiconductor targets for thin-film transistors using zinc tin oxide (ZTO) is hindered by impurity contamination from alumina balls during the sintering process, leading to off-operation issues due to excessive carrier concentration, which increases manufacturing costs and reduces the quality of the oxide semiconductor film.
Innovation Solution
Incorporating group IV or group V elements as counter doping materials with impurity concentrations equal to or less than half that of the group III elements, such as silicon oxide (SiO2) or silicon nitride (Si3N4), to control carrier concentration and suppress impurities, thereby forming a high-quality oxide semiconductor target at a lower cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If alumina balls are used for mixing zinc oxide and tin oxide powders during sintering, then the mixing process is simple and cost-effective, but group III element impurities (Al) are introduced into the oxide semiconductor target, causing excessive carrier concentration and off-operation issues in thin-film transistors
Solution Approach 1:
The patent converts the harmful effect of group III element impurities (which increase carrier concentration) into a beneficial effect by intentionally introducing group IV or group V elements as counter-doping materials. These counter-doping elements compensate for the excessive carriers generated by group III impurities, transforming the harmful impurity effect into a controlled mechanism for achieving desired electrical characteristics in the oxide semiconductor film
Solution Approach 2:
The patent introduces group IV or group V elements as intermediary substances that mediate between the harmful group III element impurities and the desired electrical properties. These intermediary elements act as counter-doping materials that compensate for the excessive carriers, allowing the use of simple alumina ball mixing while maintaining manufacturing precision through controlled impurity compensation
2Manufacturing precision
If high-purity zinc oxide and tin oxide powders are used to reduce impurity contamination, then the oxide semiconductor film quality improves, but the manufacturing cost increases
Solution Approach 1:
The patent accepts the presence of inexpensive group III element impurities from standard-purity powders and alumina balls, and converts this potential harm into a benefit by introducing group IV or group V elements as counter-doping materials. This approach maintains film quality without requiring expensive high-purity powders, thus reducing manufacturing cost while achieving the desired electrical characteristics
Solution Approach 2:
The patent changes the chemical composition parameters of the oxide semiconductor target by intentionally adding group IV or group V elements as counter-doping materials. This parameter change allows the use of standard-purity raw materials instead of expensive high-purity materials, as the counter-doping elements compensate for impurity effects and maintain the desired electrical properties in the final film
3Reliability
If group III element impurities are completely eliminated to prevent off-operation, then transistor reliability improves, but the manufacturing process becomes more complex and costly
Solution Approach 1:
The patent converts the harmful effect of group III element impurities into a beneficial mechanism by introducing group IV or group V elements as counter-doping materials. This approach maintains transistor reliability (off-operation capability) without requiring complete elimination of impurities, thus avoiding increased manufacturing process complexity. The counter-doping elements compensate for excessive carriers, enabling off-operation with simple mixing processes using alumina balls
Solution Approach 2:
The patent implements a self-service mechanism where group IV or group V elements automatically compensate for the excessive carriers generated by group III element impurities. This self-compensation mechanism maintains transistor reliability without requiring complex purification processes or strict impurity control, as the counter-doping elements naturally balance the carrier concentration through their inherent electrical properties
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 approach enables the production of high-quality oxide semiconductor targets and films with stable transistor characteristics, including improved subthreshold slope values and reduced threshold potential shift, while maintaining cost-effectiveness by controlling impurity concentrations and using affordable materials.
Implementation Method 1
a sputtering target or a deposition target, and a method of manufacturing an oxide semiconductor film with using the oxide semiconductor target by a sputtering method or a deposition method
Data Source
AI summary
A technique capable of forming an oxide semiconductor target with a high quality in a low cost is provided. In a step of manufacturing zinc tin oxide (ZTO target) used in manufacturing an oxide semiconductor forming a channel layer of a thin-film transistor, by purposely adding the group IV element (C, Si, or Ge) or the group V element (N, P, or As) to a raw material, excessive carriers caused by the group III element (Al) mixed in the step of manufacturing the ZTO target are suppressed, and a thin-film transistor having good current (Id)-voltage (Vg) characteristics is achieved.