Semiconductor Device Hydrogen Absorbing Layer Structure
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional semiconductor devices face issues with hydrogen generation near the boundary plane between the gate insulating film and semiconductor layer, leading to threshold voltage fluctuations due to aluminum electrodes reacting with water, and the hydrogen absorption effect is weakened when aluminum forms an alloy with hydrogen absorbing metals.
Innovation Solution
A semiconductor device structure comprising a hydrogen absorbing layer, a nitride layer, and an alloy layer, where the hydrogen absorbing layer is formed of a first metal like titanium, the nitride layer is formed of a nitride of the first metal, and the alloy layer is formed of an alloy of aluminum and a second metal, preventing the hydrogen absorbing layer from forming an alloy with the electrode material and maintaining its hydrogen absorption property.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hydrogen absorbing metal layer made of titanium is formed below an aluminum electrode to absorb hydrogen, then the hydrogen absorption effect is improved, but when aluminum and the hydrogen absorbing metal form an alloy, the hydrogen absorption effect is weakened
Solution Approach 1:
The electrode structure is segmented into multiple functional layers: a hydrogen absorbing layer (titanium), a nitride layer (titanium nitride), and an alloy layer (aluminum-titanium alloy). This segmentation allows each layer to perform its specific function - the hydrogen absorbing layer captures hydrogen, the nitride layer provides a diffusion barrier, and the alloy layer provides mechanical strength while limiting hydrogen absorption
Solution Approach 2:
The nitride layer acts as an intermediary between the hydrogen absorbing layer and the aluminum electrode. It prevents direct contact and alloying between titanium and aluminum while still allowing the hydrogen absorbing layer to function. The nitride layer serves as a diffusion barrier that maintains the hydrogen absorption capability of the titanium layer
2Use of energy by moving object
If aluminum electrodes are used, then good electrical conductivity is achieved, but when aluminum reacts with water in high-temperature environments, hydrogen is generated that enters the gate insulating film boundary plane causing threshold voltage fluctuation
Solution Approach 1:
The harmful hydrogen generated by aluminum reaction with water is converted into a beneficial situation by providing the hydrogen absorbing layer. The titanium layer absorbs the hydrogen that would otherwise damage the gate insulating film, transforming a harmful byproduct into a controlled element that enhances device reliability
Solution Approach 2:
The hydrogen absorbing layer and nitride layer serve as intermediaries between the aluminum electrode and the gate insulating film. These layers intercept and manage the hydrogen before it can reach the sensitive boundary plane, protecting the device while allowing the aluminum electrode to maintain its electrical functionality
3Strength
If the alloy layer thickness is increased to prevent peeling, then mechanical strength is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The thickness of the alloy layer is precisely controlled within a specific range (15 nm to 0.5 μm) to achieve the optimal balance between mechanical strength and device complexity. This parameter optimization ensures sufficient resistance to peeling while minimizing the addition of structural 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
This structure effectively restricts hydrogen from reaching the gate insulating film, stabilizes the threshold voltage, and reduces stress and peeling issues by providing an alloy layer with greater hardness than aluminum, enhancing the semiconductor device's reliability and performance.
Implementation Method 1
there is an idea of forming a hydrogen absorbing metal layer made of titanium, for example, below an aluminum electrode. By having the hydrogen absorbing metal absorb the hydrogen, it is possible to restrict the hydrogen from entering into the region near the boundary plane of the gate insulating film
Implementation Method 2
forming a nitride layer that is formed of a nitride of the first metal above the hydrogen absorbing layer
Implementation Method 3
forming an alloy layer that is formed of an alloy of aluminum and a second metal... providing an alloy layer with greater hardness than aluminum
Data Source
AI summary
To restrict the deterioration of properties in a semiconductor device due to hydrogen, provided is a semiconductor device including a semiconductor substrate; a hydrogen absorbing layer that is provided above a top surface of the semiconductor substrate and formed of a first metal having a hydrogen absorbing property; a nitride layer that is provided above the hydrogen absorbing layer and formed of a nitride of the first metal; an alloy layer that is provided above the nitride layer and formed of an alloy of aluminum and a second metal; and an electrode layer that is provided above the alloy layer and formed of aluminum. A pure metal layer of the second metal is not provided between the electrode layer and the nitride layer.