Oxide Semiconductor Gate Insulator ESD Protection
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Solution Overview
Problem
The development of semiconductor devices using oxide semiconductors faces challenges due to differences in carrier generation mechanisms compared to silicon-based semiconductors, leading to poor interface properties with gate insulating layers and increased susceptibility to electrostatic discharge (ESD) damage, which affects the reliability and yield of semiconductor devices.
Innovation Solution
A semiconductor device structure incorporating a silicon film with nitrogen, having a low hydrogen concentration and few defects, is used as a gate insulating layer, with a stacked configuration to enhance interface properties and reduce ESD damage, including a silicon nitride film with specific spin density and hydrogen content to improve electrical stability and withstand voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional gate insulating layer designed for silicon-based semiconductors is used with oxide semiconductor, then the transistor structure and process conditions can be maintained from mass production technology, but the interface properties between the gate insulating layer and oxide semiconductor are poor
Solution Approach 1:
The patent changes the material composition parameters of the gate insulating layer by incorporating nitrogen into silicon oxide to form silicon oxynitride. This parameter change improves the interface properties with oxide semiconductor while maintaining compatibility with existing transistor structures and mass production processes.
Solution Approach 2:
The patent uses a composite gate insulating layer structure consisting of silicon oxide and silicon nitride layers. This composite material approach combines the benefits of both materials: silicon oxide provides good interface properties with oxide semiconductor, while silicon nitride provides high breakdown voltage and ESD protection.
2Productivity
If a glass substrate with high insulating properties and large area is used to achieve high productivity and low cost, then the manufacturing efficiency is improved, but the device becomes susceptible to electrostatic discharge (ESD) damage
Solution Approach 1:
The patent converts the high insulating property of the glass substrate, which causes ESD susceptibility, into a benefit by using silicon nitride in the gate insulating layer. The silicon nitride layer provides high breakdown voltage and ESD protection, transforming the ESD vulnerability into enhanced ESD resistance while maintaining the advantages of large-area glass substrates for high productivity.
Solution Approach 2:
The patent provides beforehand cushioning against ESD damage by incorporating a silicon nitride layer in the gate insulating layer before ESD events occur. This layer acts as a protective barrier that absorbs and dissipates ESD energy, preventing damage to the oxide semiconductor and other sensitive components.
3Reliability
If the hydrogen concentration in the silicon nitride film is reduced to improve interface properties, then the electrical stability is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent changes the manufacturing parameters by controlling the nitrogen gas flow rate and deposition conditions during sputtering to achieve the desired hydrogen concentration range (5-20 at%). This parameter control approach balances electrical stability improvement with manufacturability, avoiding excessive precision requirements.
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 proposed solution results in a highly reliable and electrically stable semiconductor device with reduced risk of ESD damage, maintaining high productivity and yield by utilizing a silicon nitride film with controlled nitrogen content and hydrogen concentration in the gate insulating layer.
Implementation Method 1
a silicon film containing nitrogen and including a small number of defects and a silicon film containing nitrogen and having a low hydrogen concentration
Implementation Method 2
there arises the problem of electrostatic discharge (ESD) damage. This problem should inevitably be taken into consideration also in the case of using an oxide semiconductor material
Data Source
AI summary
A highly reliable semiconductor device the yield of which can be prevented from decreasing due to electrostatic discharge damage is provided. A semiconductor device is provided which includes a gate electrode layer, a first gate insulating layer over the gate electrode layer, a second gate insulating layer being over the first gate insulating layer and having a smaller thickness than the first gate insulating layer, an oxide semiconductor layer over the second gate insulating layer, and a source electrode layer and a drain electrode layer electrically connected to the oxide semiconductor layer. The first gate insulating layer contains nitrogen and has a spin density of 1×1017 spins/cm3 or less corresponding to a signal that appears at a g-factor of 2.003 in electron spin resonance spectroscopy. The second gate insulating layer contains nitrogen and has a lower hydrogen concentration than the first gate insulating layer.