Oxide Semiconductor Transistor Gate Insulator Nitrogen Control
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Solution Overview
Problem
The electrical characteristics of transistors using oxide semiconductors are prone to variation due to nitrogen contamination, leading to unstable threshold voltage and reliability issues, particularly in flat panel displays and integrated circuits.
Innovation Solution
A semiconductor device structure incorporating an oxide semiconductor film with a gate insulating film and a protective film, both having controlled nitrogen oxide content, measured by electron spin resonance spectroscopy, to minimize carrier traps and maintain low spin density, thereby stabilizing the electrical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nitrogen is contained in films in contact with oxide semiconductor film, then carrier supply increases, but electrical characteristics change and reliability deteriorates
Solution Approach 1:
The patent extracts and removes nitrogen from films in contact with the oxide semiconductor film through controlled heating treatment. This eliminates the harmful nitrogen contamination that causes carrier supply variations and electrical characteristic changes, thereby improving reliability without compromising the semiconductor device's functionality
Solution Approach 2:
The patent applies parameter changes by controlling the heating temperature and atmosphere during manufacturing and processing. By optimizing these parameters, nitrogen is selectively removed from critical films while preserving the oxide semiconductor film's properties, resolving the contradiction between nitrogen's beneficial carrier supply and its harmful contamination effects
2Reliability
If hydrogen is removed from oxide semiconductor to suppress threshold voltage variation, then electrical stability improves, but manufacturing complexity increases
Solution Approach 1:
The patent merges multiple functions into a single heating treatment process that simultaneously removes both hydrogen and nitrogen from films in contact with the oxide semiconductor film. This combined treatment achieves threshold voltage stability and electrical characteristic stability without requiring separate manufacturing steps, thereby improving reliability while avoiding increased manufacturing complexity
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 effectively reduces changes in threshold voltage and improves the reliability and power efficiency of transistors by controlling nitrogen oxide content, resulting in more stable and reliable semiconductor devices.
Implementation Method 1
The spin density of the gate insulating film or the protective film measured by electron spin resonance (ESR) spectroscopy is lower than 1×1018 spins/cm3
Data Source
AI summary
In a semiconductor device using a transistor including an oxide semiconductor, a change in electrical characteristics is suppressed and reliability is improved. The semiconductor device includes a gate electrode over an insulating surface; an oxide semiconductor film overlapping with the gate electrode; a gate insulating film that is between the gate electrode and the oxide semiconductor film and in contact with the oxide semiconductor film; a protective film in contact with a surface of the oxide semiconductor film that is an opposite side of a surface in contact with the gate insulating film; and a pair of electrodes in contact with the oxide semiconductor film. The spin density of the gate insulating film or the protective film measured by electron spin resonance spectroscopy is lower than 1×1018 spins/cm3, preferably higher than or equal to 1×1017 spins/cm3 and lower than 1×1018 spins/cm3.