Hydrogenated Polysilicon TFT Defect Curing via Buffer Layer
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Solution Overview
Problem
Polycrystalline silicon layers used in semiconductor devices, such as TFTs, often contain defects like dangling bonds and grain boundaries that impede charge carrier mobility, affecting transistor performance.
Innovation Solution
A semiconductor device and manufacturing method that incorporate a hydrogenated polycrystalline silicon layer, formed by depositing a hydrogen-containing silicon nitride buffer layer and a thin silicon oxide layer on a substrate, followed by heat treatment to diffuse hydrogen into the polycrystalline silicon layer, thereby curing internal defects and improving transistor characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polycrystalline silicon layer is used as a semiconductor layer in TFTs, then high charge mobility and high-speed operation are achieved, but defects such as dangling bonds and grain boundaries impede charge carrier mobility and affect transistor performance
Solution Approach 1:
A hydrogen-containing buffer layer is formed prior to the polycrystalline silicon layer to proactively supply hydrogen that will later diffuse into and cure defects in the polycrystalline silicon layer, improving transistor performance before the defects can significantly degrade device operation
Solution Approach 2:
A hydrogen-containing buffer layer acts as an intermediary between the substrate and the polycrystalline silicon layer, serving as a hydrogen reservoir that diffuses hydrogen into the polycrystalline silicon to cure defects without requiring direct contact with the polycrystalline silicon during formation
2Reliability
If a thick silicon oxide layer is used to isolate the silicon nitride buffer layer, then impurity diffusion is prevented, but hydrogen diffusion from the buffer layer to the polycrystalline silicon layer is blocked
Solution Approach 1:
The silicon oxide layer is used with locally optimized thickness: thin enough (100-500 nm) to allow hydrogen diffusion from the buffer layer to the polycrystalline silicon layer, but sufficient to provide impurity barrier functionality in the same region
Solution Approach 2:
The thickness parameter of the silicon oxide layer is precisely controlled within a specific range (100-500 nm) to simultaneously satisfy two opposing requirements: allowing hydrogen diffusion while blocking impurity diffusion, resolving the contradiction through parameter optimization
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 approach enhances the charge mobility and uniformity of transistor characteristics by effectively bonding hydrogen to defects within the polycrystalline silicon layer, reducing impurity diffusion and improving the overall performance of TFTs.
Implementation Method 1
heat treatment to diffuse hydrogen into the polycrystalline silicon layer
Implementation Method 2
depositing a hydrogen-containing silicon nitride buffer layer
Implementation Method 3
depositing a thin silicon oxide layer
Data Source
AI summary
A semiconductor device and a method of manufacturing the same are disclosed. In one embodiment, the semiconductor device includes a substrate, a first silicon nitride layer formed over the substrate, a first silicon oxide layer formed directly on the first silicon nitride layer and having a thickness of about 1000 Å or less, and a hydrogenated polycrystalline silicon layer formed directly on the first silicon oxide layer.