Boron Diffusion Agent for Nano-Structure Coating
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Solution Overview
Problem
Existing methods for diffusing impurity diffusion ingredients into semiconductor substrates with nano-scale three-dimensional structures face challenges such as the formation of point defects, uneven ion implantation, and difficulties in uniformly coating and depositing oxide films, leading to performance deterioration and crystal damage.
Innovation Solution
A diffusion agent composition containing a complex boron compound and a hydrolyzable Si compound that produces a silanol group, allowing for even coating and diffusion of boron into semiconductor substrates with nano-scale voids, using a method that involves coating and subsequent heat treatment to form a thin film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ion implantation method is used to diffuse impurity into semiconductor substrate, then impurity diffusion can be achieved, but point defects and point defect clusters are formed near the surface
Solution Approach 1:
A silicon oxide film is introduced as an intermediary layer between the ion implantation process and the semiconductor substrate. This film acts as a buffer that absorbs implantation damage and prevents direct formation of point defects in the substrate, while still allowing impurity diffusion to occur effectively
2Manufacturing precision
If ion implantation method is used on semiconductor substrate with nano-scale three-dimensional structure, then impurity diffusion is attempted, but uniform implantation into side surfaces and inner surfaces of concaves is difficult
Solution Approach 1:
The silicon oxide film serves as a mediator that enables uniform impurity distribution across complex three-dimensional surfaces. The film can be deposited conformally on side surfaces and inner surfaces of concaves, providing a uniform starting layer for subsequent impurity diffusion that overcomes the limitations of direct ion implantation geometry
Solution Approach 2:
The patent replaces the mechanical ion implantation process with a chemical diffusion process through the silicon oxide film. Instead of physically shooting ions at the substrate, impurities diffuse thermally through the oxide layer, which naturally conforms to complex geometries and achieves uniform distribution without the directional limitations of ion beam physics
3Reliability
If ion implantation is performed on semiconductor substrate with fine fins, then impurity diffusion is achieved, but crystal damage occurs causing device property variation and stand-by leak current
Solution Approach 1:
The silicon oxide film acts as a protective intermediary that absorbs implantation damage. By performing ion implantation into the oxide film rather than directly into the semiconductor crystal, the film serves as a sacrificial layer that protects the underlying crystal structure from damage, preventing dislocation formation and maintaining device reliability
Solution Approach 2:
The silicon oxide film is formed on the semiconductor substrate surface before ion implantation. This preliminary action creates a protective buffer layer that prevents subsequent implantation damage from reaching and damaging the crystal structure, thereby preventing dislocation formation and maintaining device reliability
4Quantity of substance
If CVD method is used to form oxide film with impurity diffusion ingredient, then oxide film deposition is achieved, but overhang phenomenon prevents uniform coating and blocks openings of concaves
Solution Approach 1:
The patent replaces the CVD physical vapor deposition process with a spin coating liquid application method. Spin coating allows the coating solution to be uniformly distributed across the substrate surface through centrifugal force, naturally achieving uniform thickness even on three-dimensional structures without the line-of-sight limitations that cause the overhang phenomenon in CVD
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 solution enables uniform impurity diffusion into semiconductor substrates with nano-scale structures, reducing defects and improving the properties of devices like CMOS image sensors and logic LSI devices by ensuring even boron distribution and suppressing external diffusion.
Implementation Method 1
a Si compound (B) that is hydrolyzable to produce a silanol group
Implementation Method 2
an impurity diffusion ingredient is diffused into a semiconductor substrate by a thin film formed using the diffusion agent composition
Data Source
AI summary
A diffusion agent composition that, even when a semiconductor substrate which is an object into which an impurity diffusion ingredient is to be diffused has, on a surface thereof, a three-dimensional structure having nano-scale fine voids on a surface thereof, can be evenly coated on the whole area of an inner surface of the fine voids, whereby boron can be diffused into the semiconductor substrate, and a method for manufacturing a semiconductor substrate using the composition. The composition includes an impurity diffusion ingredient and a hydrolyzable Si compound to produce a silanol group, the impurity diffusion ingredient containing a complex compound containing boron having a specific structure.