AlN Seed Crystal Formation for Semiconductor Device Manufacturing
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Solution Overview
Problem
Existing semiconductor manufacturing methods often result in crystal defects such as pits in nitride semiconductor layers, which affect the quality and performance of semiconductor devices.
Innovation Solution
A method involving the formation of AlN seed crystals on a single-crystal substrate by etching a first AlN layer, followed by growing a second AlN layer using these seeds as nuclei, reduces crystal defects by stabilizing the ammonia gas flow and optimizing growth conditions, allowing for uniform dispersion and reduced variations in seed crystal size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a continuous AlN buffer layer is formed on the SiC substrate, then the layer provides good coverage, but it results in high density of pits and crystal defects
Solution Approach 1:
The continuous AlN buffer layer is segmented into discrete AlN seed crystal islands with controlled density and size. This segmentation approach transforms the uniform continuous layer into distributed discrete nuclei, reducing pit formation while maintaining adequate coverage for subsequent semiconductor layer growth
Solution Approach 2:
Instead of uniform buffer layer properties throughout, the invention creates localized AlN seed crystals with specific size distributions and spatial arrangements. Each seed crystal serves as a localized growth nucleus with optimized properties, allowing different regions to have tailored characteristics that reduce overall defect density
2Reliability
If AlN seed crystals are formed by etching the AlN layer, then crystal defects are reduced, but the etching process adds process complexity
Solution Approach 1:
The buffer layer formation and seed crystal creation processes are merged into a single integrated process. The AlN buffer layer is deposited and simultaneously patterned into seed crystals through in-situ etching, combining what would traditionally be separate deposition and patterning steps into one unified manufacturing operation
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 effectively minimizes crystal defects in the semiconductor layer, enhancing the crystallinity and reducing variations, leading to improved device performance and reliability.
Implementation Method 1
forming a plurality of pieces of AlN seed crystals on the first main surface from the first AlN layer by etching a portion of the first AlN layer
Implementation Method 2
forming a second AlN layer on the first main surface using the AlN seed crystals as growth nuclei
Data Source
AI summary
A method of manufacturing a semiconductor device includes forming a first AlN layer on a first main surface of a single-crystal substrate, partly etching the first AlN layer to form a plurality of pieces of AlN seed crystals on the first main surface from the first AlN layer, and forming a second AlN layer on the first main surface using the AlN seed crystals as growth nuclei.