Amorphous Nitride Protection Layer for Semiconductor Substrate Crack Prevention
Solution Overview
Problem
The growth of nitride semiconductor layers on silicon substrates often results in cracks due to lattice constant and thermal expansion coefficient differences, leading to defects and reduced yield in high electron mobility transistors (HEMTs), and existing protection methods like silicon nitride films can cause abnormal growth and composition issues.
Innovation Solution
A semiconductor crystal substrate is created with an amorphous nitride protection layer on the periphery and a crystallized internal layer, using Atomic Layer Deposition (ALD) and plasma treatment to prevent crack formation and ensure proper epitaxial growth of semiconductor layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protection layer such as silicon nitride is formed on the outer periphery of the substrate, then cracks are prevented from being formed on the substrate periphery, but abnormal growth of buffer layer and semiconductor layer occurs near the protection layer
Solution Approach 1:
The patent changes the physical and chemical parameters of the protection layer by forming it in an amorphous state rather than a crystalline state. This parameter change prevents the protection layer from causing abnormal epitaxial growth while maintaining its crack prevention function. The amorphous structure does not provide a template for crystal growth, thereby eliminating the source of abnormal growth near the protection layer boundary.
Solution Approach 2:
The patent utilizes phase transition by forming the protection layer in an amorphous phase instead of a crystalline phase. This phase transition is achieved through specific deposition conditions that result in an amorphous structure. The amorphous phase lacks long-range order, preventing it from inducing abnormal crystal growth in the underlying buffer and semiconductor layers while still providing mechanical protection against cracks.
2Reliability
If a protection layer is formed on the outer periphery of the substrate, then cracks are prevented, but it is technically difficult to form the protection layer only on the periphery and costs increase
Solution Approach 1:
The patent applies partial action by forming the protection layer with a specific radial width range (5-50 μm from the substrate periphery) rather than covering the entire substrate. This partial coverage is sufficient to prevent cracks at the critical periphery region where cracks typically form, while avoiding the need to precisely pattern the protection layer across the entire substrate surface, thereby simplifying the manufacturing process.
3Reliability
If protection layer is formed on substrate periphery, then cracks are prevented, but source gas diffuses from protection layer causing abnormal growth and composition variations
Solution Approach 1:
The patent changes the physical state parameter of the protection layer from crystalline to amorphous. This parameter change eliminates the crystal structure that would otherwise facilitate source gas diffusion and incorporation into the buffer and semiconductor layers. The amorphous structure provides a barrier that prevents source gas from diffusing into the growing layers, thereby maintaining stable and uniform composition in the buffer and semiconductor layers near the protection layer boundary.
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 prevents crack formation on the substrate periphery, increases manufacturing yield, and allows for the production of high-quality HEMTs at lower costs by ensuring proper growth and composition of semiconductor layers.
Implementation Method 1
the protection layer is in an amorphous state in a peripheral area at an outer peripheral part of the substrate, and the protection layer is crystallized in an internal area of the protection layer that is inside the peripheral area of the protection layer
Implementation Method 2
using Atomic Layer Deposition (ALD) and plasma treatment to prevent crack formation
Implementation Method 3
using Atomic Layer Deposition (ALD) and plasma treatment to prevent crack formation
Implementation Method 4
the protection layer is crystallized in an internal area of the protection layer that is inside the peripheral area of the protection layer
Data Source
AI summary
A semiconductor crystal substrate includes a substrate; and a protection layer formed by applying nitride on a surface of the substrate. The protection layer is in an amorphous state in a peripheral area at an outer peripheral part of the substrate, and the protection layer is crystallized in an internal area of the protection layer that is inside the peripheral area of the protection layer.