Semiconductor Surface Oxidation via High Energy Electromagnetic Radiation
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Solution Overview
Problem
Conventional methods face challenges in forming high-quality dielectric materials for MOS transistor devices as device sizes decrease, particularly in achieving defect-free oxide layers for gate insulating layers in semiconductor devices.
Innovation Solution
A method involving a semiconductor substrate with a native oxide layer, treated with a wet cleaning process and subjected to a high energy electromagnetic radiation in an oxygen-bearing environment to form an oxide layer with minimal imperfections, allowing for the creation of a thin, pinhole-free oxide layer, and optionally forming a nitride layer over this oxide layer to create an oxide on nitride on oxide stack structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional thermal processing methods are used to form oxide layers, then the processing time is long and thermal budget is high, but the oxide quality deteriorates with pinholes and imperfections
Solution Approach 1:
The patent replaces conventional thermal field processing with electromagnetic radiation field processing. Specifically, it uses high-energy electromagnetic radiation (UV to visible light range, 300-800nm) to directly excite oxygen molecules and form reactive oxygen species that oxidize the silicon surface, eliminating the need for prolonged thermal treatment and achieving high-quality oxide layers without pinholes in significantly reduced time
Solution Approach 2:
The patent changes the fundamental processing parameter from thermal energy to electromagnetic radiation energy. By using photons in the 300-800nm wavelength range with sufficient energy density, the process directly drives oxygen incorporation into the silicon lattice through photochemical reactions rather than thermal diffusion, achieving superior oxide quality with controlled thickness and no defects
2Productivity
If device geometry is reduced to increase circuit density, then more devices can be fabricated per wafer, but the formation of high-quality dielectric materials becomes increasingly difficult
Solution Approach 1:
The patent replaces thermal field processing with electromagnetic radiation field processing to form dielectric materials. By using high-energy photons (300-800nm) to generate reactive oxygen species that directly oxidize the silicon surface, the process achieves atomic-level control and uniformity in oxide layer formation, ensuring high-quality dielectric materials even at reduced device geometries where thermal processes would create defects
Solution Approach 2:
The patent employs electromagnetic radiation to generate highly reactive oxygen species that act as strong oxidants. These activated oxygen species rapidly and uniformly oxidize the silicon surface to form high-quality oxide layers, enabling precise dielectric material formation at small device dimensions where conventional oxidation would be insufficient or produce defects
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 enhances device yields by producing high-quality dielectric layers with reduced thermal budget, compatible with conventional processes and equipment, and allows for the formation of dense, imperfection-free oxide layers, improving the complexity and performance of integrated circuits.
Implementation Method 1
subjecting the surface region to a high energy electromagnetic radiation having wavelengths ranging from about 300 to about 800 nanometers for a time period of less than 10 milli-seconds to increase a temperature of the surface region to greater than 1000 Degrees Celsius
Implementation Method 2
subjecting the surface region to an oxygen bearing environment and subjecting the surface region to a high energy electromagnetic radiation
Data Source
AI summary
A method for fabricating semiconductor devices, e.g., SONOS cell. The method includes providing a semiconductor substrate (e.g., silicon wafer, silicon on insulator) having a surface region, which has a native oxide layer. The method includes treating the surface region to a wet cleaning process to remove a native oxide layer from the surface region. In a specific embodiment, the method includes subjecting the surface region to an oxygen bearing environment and subjecting the surface region to a high energy electromagnetic radiation having wavelengths ranging from about 300 to about 800 nanometers for a time period of less than 10 milli-seconds to increase a temperature of the surface region to greater than 1000 Degrees Celsius. In a specific embodiment, the method causes formation of an oxide layer having a thickness of less than 10 Angstroms. In a preferred embodiment, the oxide layer is substantially free from pinholes and other imperfections. In a specific embodiment, the oxide layer is a gate oxide layer.