Semiconductor Wafer Selective Nitride Buffer Growth
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing methods for manufacturing semiconductor wafers face challenges in achieving high-quality epitaxial layers due to stress and defects at the junction interface caused by multiple crystal surfaces with different growth directions, leading to warpage and reduced reliability of LED chips.
Innovation Solution
A method involving the selective growth of a nitride buffer layer on a patterned substrate using a sacrificial layer, where the buffer layer is grown only on the plane surface and not on the raised surface, allowing the epitaxial layer to grow along the normal direction without lateral growth, thereby avoiding stress and defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a nitride buffer layer is grown on both the raised surface and plane surface of the patterned substrate, then the coverage is complete, but stress and defects occur at the junction interface due to multiple crystal growth directions
Solution Approach 1:
The patent applies local quality by making the buffer layer coverage non-uniform: it is present only on the plane surface area and intentionally absent from the raised surface area. This localized presence ensures that the epitaxial layer grows in a single direction on the plane surface, avoiding the stress and defects that would occur at junction interfaces where multiple crystal growth directions meet.
2Area of stationary object
If the epitaxial layer grows laterally along with the normal direction, then the coverage area increases, but warpage occurs due to stress at the junction interface
Solution Approach 1:
The patent uses local quality by restricting the buffer layer to the plane surface area only, which in turn constrains the epitaxial layer growth to occur solely on the plane surface. This prevents lateral growth onto the raised surface, eliminating the warpage that would result from stress at junction interfaces between differently oriented crystal surfaces.
3Device complexity
If multiple crystal surfaces with different growth directions are present, then the structural complexity increases, but defects and reduced reliability result from stress at junction interfaces
Solution Approach 1:
The patent applies the extraction principle by removing the buffer layer from the raised surface area, thereby eliminating the formation of junction interfaces where multiple crystal growth directions would meet. This extraction of the buffer layer from specific regions prevents the creation of complex multi-directional crystal structures and their associated 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 approach suppresses warpage and improves the uniformity of the epitaxial wafer, reducing defects and enhancing the reliability of LED chips by ensuring the epitaxial layer grows along a single direction, thus improving the crystal quality and light extraction efficacy.
Implementation Method 1
growing an epitaxial layer on the nitride buffer layer. A crystal surface of the epitaxial layer grows along a normal direction of the patterned substrate
Implementation Method 2
removing a top portion of the original nitride buffer layer by a first wet etching process or a dry etching process
Implementation Method 3
removing a top portion of the original nitride buffer layer by a first wet etching process or a dry etching process
Data Source
AI summary
Provided is a method for manufacturing a semiconductor wafer and a semiconductor wafer. The method includes: disposing a sacrificial layer on a first surface and a second surface of a patterned substrate, the patterned substrate comprising the first surface and the second surface having different normal directions; exposing the first surface by removing the first portion of the sacrificial layer disposed on the first surface; growing an original nitride buffer layer on the first surface and the second portion of the sacrificial layer; partially lifting off the second portion of the sacrificial layer disposed on the second surface such that at least one sub-portion of the second portion of the sacrificial layer remains on the second surface of the patterned substrate; and growing an epitaxial layer on the original nitride buffer layer, where a crystal surface of the epitaxial layer grows along a normal direction of the patterned substrate.