SiO2 Layer Hydrogen Passivation for Low-Temperature BTI Reliability
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Solution Overview
Problem
Bias temperature instability (BTI) in SiO2 layers, particularly negative BTI (NBTI), remains a challenge due to electrically active defects like hydroxyl-E' and hydrogen bridge defects, which are difficult to address under thermal budget constraints in advanced semiconductor technologies.
Innovation Solution
Exposure of SiO2 layers to atomic hydrogen at relatively low temperatures (100-300 °C) effectively passivates these defects, reducing charge trapping and improving NBTI reliability, with subsequent molecular hydrogen treatment further enhancing stability and reducing positive oxide charge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-temperature fabrication steps (e.g., rapid thermal oxidation at 900+ °C or reliability anneal at >800 °C) are used to minimize hole trap density in SiO2, then NBTI reliability is improved, but thermal budget is consumed which impedes stacking of multiple semiconductor device tiers in sequential 3D integration
Solution Approach 1:
The patent changes the physical-chemical state of hydrogen from molecular (H2) to atomic (H) form through plasma generation, enabling defect passivation at low temperatures (25-450°C). This parameter change allows achieving NBTI improvement without consuming thermal budget, resolving the contradiction between reliability improvement and temperature constraint
Solution Approach 2:
The patent replaces the thermal mechanism (high-temperature annealing) with a plasma-based chemical mechanism. By using plasma to generate atomic hydrogen that passivates defects at low temperatures, the mechanical/thermal system is substituted with a plasma chemical system, achieving the same reliability improvement without high temperature
2Reliability
If dipole-forming layers are inserted at SiO2-HfO2 interface to improve PBTI reliability at low thermal budget, then charge trapping is reduced, but the approach for NBTI improvement remains insufficient without aggressive SiO2 interlayer scaling
Solution Approach 1:
The patent applies atomic hydrogen treatment that provides universal improvement for both NBTI and PBTI reliability through a single process step. This multi-functional approach eliminates the need for separate dipole-forming layer insertion for PBTI and aggressive scaling for NBTI, achieving both reliability improvements simultaneously without manufacturing precision constraints
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 significantly reduces NBTI-induced trapped charge sheet density, surpassing the reliability of SiO2 layers formed at higher temperatures, while maintaining low thermal budget compatibility, and improves interface stability and breakdown robustness.
Implementation Method 1
exposure of the SiO 2 layer to atomic hydrogen (H*) generated in a plasma... effectively passivation of electrically active defects-such as hydroxyl-E'- and hydrogen bridge defects
Implementation Method 2
a) exposing the SiO 2 layer to atomic hydrogen (H*) generated in a plasma
Data Source
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AI summary
In a first aspect, the present invention relates to a method for improving a bias temperature instability of a SiO2 layer, comprising: (a) exposing the SiO2 layer to atomic hydrogen.