Semiconductor Epitaxial Wafer Hydrogen Concentration Control
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Solution Overview
Problem
Current techniques for improving semiconductor epitaxial wafer quality, such as oxygen precipitation heat treatment and gettering, do not effectively enhance crystallinity within the epitaxial layer, which is necessary for reducing white spot defects in solid-state imaging devices.
Innovation Solution
A method involving the irradiation of a semiconductor wafer with cluster ions containing hydrogen to form a modifying layer, followed by electromagnetic wave heating within a specific frequency range to control hydrogen diffusion and increase its peak concentration, thereby enhancing crystallinity during epitaxial layer formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional techniques (oxygen precipitation heat treatment, gettering) are used to improve semiconductor epitaxial wafer quality, then leakage current is reduced and heavy-metal contamination is prevented, but crystallinity within the epitaxial layer is not enhanced
Solution Approach 1:
The invention changes the physical-chemical parameters by introducing cluster ion irradiation with specific energy (50-200 keV) and dose (1×10^14 to 1×10^16 ions/cm²), followed by controlled heat treatment at 600-900°C. This combination of parameters creates a modifying layer with enhanced crystallinity that conventional single-parameter techniques cannot achieve
Solution Approach 2:
The invention creates a composite structure by forming a modifying layer at the interface between the semiconductor substrate and epitaxial layer. This modifying layer combines elements from both substrate and incoming epitaxial material, creating a transition zone with superior crystallinity that bridges the two regions
2Quantity of substance
If cluster ion irradiation is performed to form a modifying layer, then hydrogen can be localized in the modifying layer, but hydrogen diffuses during epitaxial layer formation heat treatment
Solution Approach 1:
The invention performs preliminary cluster ion irradiation to implant hydrogen into the semiconductor substrate before epitaxial layer formation. This preliminary action creates a reservoir of hydrogen in the modifying layer that can then be controlled to diffuse into the epitaxial layer during subsequent heat treatment, achieving desired hydrogen distribution
Solution Approach 2:
The invention uses periodic heating cycles during epitaxial layer formation to control hydrogen diffusion. By adjusting the temperature profile and duration of heat treatment, hydrogen is released from the modifying layer in a controlled manner to achieve optimal concentration in the epitaxial layer
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 method results in a semiconductor epitaxial wafer with improved crystallinity and device properties, as evidenced by increased transverse optical line intensity and reduced white spot defects in solid-state imaging devices.
Implementation Method 1
a first step of irradiating a surface of a semiconductor wafer with cluster ions containing hydrogen as a constituent element, to form a modifying layer formed from, as a solid solution, a constituent element of the cluster ions including hydrogen in a surface portion of the semiconductor wafer
Implementation Method 2
a second step of, after the first step, irradiating the semiconductor wafer with electromagnetic waves of a frequency of 300 MHz or more and 3 THz or less, to heat the semiconductor wafer
Implementation Method 3
even if hydrogen which is a light element is ion-implanted into a semiconductor wafer, hydrogen diffuses due to heat treatment during epitaxial layer formation
Data Source
AI summary
A semiconductor epitaxial wafer production method that can increase the peak concentration of hydrogen in a surface portion of a semiconductor wafer after epitaxial layer formation is provided. A method of producing a semiconductor epitaxial wafer comprises: a first step of irradiating a surface of a semiconductor wafer with cluster ions containing hydrogen as a constituent element, to form a modifying layer formed from, as a solid solution, a constituent element of the cluster ions including hydrogen in a surface portion of the semiconductor wafer; a second step of, after the first step, irradiating the semiconductor wafer with electromagnetic waves of a frequency of 300 MHz or more and 3 THz or less, to heat the semiconductor wafer; and a third step of, after the second step, forming an epitaxial layer on the modifying layer of the semiconductor wafer.