Oxide Semiconductor Transistor Doping via Metal Insulator
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Solution Overview
Problem
Current semiconductor devices using oxide semiconductors face challenges in achieving high on-state characteristics, which limits their speed and performance in electronic applications.
Innovation Solution
The method involves forming low-resistance regions in an oxide semiconductor film by adding a dopant through an insulating film containing a metal element, such as aluminum or titanium, using techniques like ion implantation, to enhance the channel formation region's conductivity and mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a dopant is added directly to the oxide semiconductor film without an insulating film barrier, then the doping process is simpler, but the dopant distribution becomes uncontrollable and damages the oxide semiconductor film structure
Solution Approach 1:
An insulating film containing metal elements (such as aluminum, titanium, or their oxides/nitrides) is introduced as an intermediary layer between the dopant source and the oxide semiconductor film. This intermediate film enables controlled dopant diffusion while protecting the oxide semiconductor film structure, resolving the contradiction between process simplicity and doping precision.
Solution Approach 2:
The insulating film is formed on the oxide semiconductor film surface before the dopant addition process. This preliminary action prepares a controlled diffusion pathway that will guide the dopant distribution during subsequent doping steps, ensuring both ease of manufacture and manufacturing precision.
2Reliability
If the oxide semiconductor film is highly purified to improve transistor characteristics, then on-state characteristics improve, but the manufacturing process becomes more complex and time-consuming
Solution Approach 1:
The oxide semiconductor film is subjected to preliminary purification treatments (such as heat treatment in an oxygen atmosphere or plasma treatment) before transistor fabrication. This advance purification reduces the need for complex subsequent processing steps, improving on-state characteristics while managing manufacturing complexity.
Solution Approach 2:
The physical and chemical parameters of the oxide semiconductor film (such as oxygen content, crystal structure, and impurity concentration) are optimized through controlled heat treatment and deposition conditions. By adjusting these parameters, high reliability is achieved without proportionally increasing manufacturing process complexity.
3Speed
If the channel length is reduced to increase operating speed, then high-speed operation is achieved, but short-channel effects increase and control becomes difficult
Solution Approach 1:
The insulating film with metal elements is applied locally at the source and drain regions adjacent to the channel, creating localized doping zones. This local quality enhancement allows for shorter channel lengths while maintaining adequate control over short-channel effects through concentrated dopant distribution in critical regions.
Solution Approach 2:
The doping concentration and profile are precisely controlled by adjusting the insulating film thickness and dopant addition parameters. This enables optimization of the electric field distribution in short-channel devices, maintaining reliability even as channel length is reduced for higher speed operation.
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 improves the on-state characteristics and field-effect mobility of the transistor, enabling high-speed operation and response, thus creating a high-performance semiconductor device with improved reliability.
Implementation Method 1
a dopant is added to an oxide semiconductor film by an implantation method through an insulating film including a metal element
Data Source
AI summary
A transistor using an oxide semiconductor, which has good on-state characteristics is provided. A high-performance semiconductor device including the transistor capable of high-speed response and high-speed operation is provided. In a manufacturing method of the transistor including the oxide semiconductor film including a channel formation region, an insulating film including a metal element is formed over the oxide semiconductor film, and low-resistance regions in which a dopant added through the insulating film by an implantation method is included are formed in the oxide semiconductor film. The channel formation region is positioned between the low-resistance regions in the channel length direction.