Nitride Semiconductor Annealing for Vacancy Defect Control
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Solution Overview
Problem
Conventional methods for manufacturing semiconductor devices with nitride semiconductor layers face challenges in preventing vacancy defects from forming and escaping during annealing, which can affect the p-type characteristics and interface quality of the semiconductor layers.
Innovation Solution
A two-step annealing process is employed, where the first annealing is performed at a lower temperature without a protective film to allow vacancy defects to escape and react with nitrogen atoms, followed by a second annealing at a higher temperature with a protective film to activate impurities, thereby reducing defects and improving p-type well characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a protective film is provided on the nitride semiconductor layer before annealing, then the nitride semiconductor layer is protected from damage, but vacancy defects are prevented from escaping to the surface and disappearing
Solution Approach 1:
The annealing process is divided into two distinct stages: a first annealing stage without a protective film to eliminate vacancy defects, and a second annealing stage with a protective film to activate impurities. This segmentation allows each stage to fulfill its specific function without compromising the other, resolving the contradiction between defect elimination and layer protection.
Solution Approach 2:
The first annealing treatment is performed preliminarily before forming the protective film. This preliminary action eliminates vacancy defects from the nitride semiconductor layer before the protective film is applied, ensuring that subsequent high-temperature annealing with the protective film in place does not trap vacancy defects, thus resolving the contradiction.
2Reliability
If annealing is performed at high temperature to activate impurities, then p-type characteristics are improved, but vacancy defects aggregate and remain in the layer
Solution Approach 1:
The annealing process is segmented into two temperature stages: a first lower-temperature annealing to eliminate vacancy defects, and a second higher-temperature annealing to activate impurities. This segmentation prevents vacancy defect aggregation during high-temperature treatment while still achieving effective impurity activation, resolving the contradiction between p-type characteristic improvement and manufacturing precision.
Solution Approach 2:
The first annealing treatment is performed preliminarily to eliminate vacancy defects before the second high-temperature annealing. This preliminary defect elimination ensures that when high-temperature annealing is subsequently applied to activate impurities, vacancy defects do not aggregate, thus resolving the contradiction between impurity activation and defect aggregation.
3Reliability
If annealing is performed without a protective film to allow vacancy defects to escape, then defect reduction is achieved, but the nitride semiconductor layer may be damaged
Solution Approach 1:
The annealing temperature is controlled to be at or below 1200°C during the first annealing stage without a protective film. This parameter control allows vacancy defects to escape to the surface and be eliminated while preventing thermal decomposition and damage to the nitride semiconductor layer, thus resolving the contradiction between defect elimination and layer integrity.
Solution Approach 2:
The first annealing treatment is performed preliminarily to eliminate vacancy defects before the protective film is formed and before the second high-temperature annealing. This preliminary action achieves defect reduction under controlled conditions, and subsequent protective film formation ensures layer integrity during final impurity activation, resolving the contradiction.
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 reduces nitrogen vacancy defects, enhances p-type well performance, and maintains a smooth interface between the channel region and gate insulator, improving the overall semiconductor device operation.
Implementation Method 1
a first annealing may be performed on the nitride semiconductor layer at a first temperature within an atmosphere of a nitrogen atom containing gas without providing a protective film on the nitride semiconductor layer
Implementation Method 2
The first temperature may be a temperature at which thermal decomposition of the nitride semiconductor layer does not proceed within the atmosphere of the nitrogen atom containing gas
Implementation Method 3
During the implanting, impurities may be implanted into the nitride semiconductor layer
Implementation Method 4
a second annealing may be performed on the nitride semiconductor layer at a second temperature that is higher than the first temperature
Data Source
AI summary
When a nitride semiconductor layer into which impurity ions have been implanted is subjected to annealing after a protective film is provided on the nitride semiconductor layer, vacancy defects may be disadvantageously prevented from escaping outside through the surface of the nitride semiconductor layer and disappearing. A manufacturing method of a semiconductor device including a nitride semiconductor layer is provided. The manufacturing method includes implanting impurities into the nitride semiconductor layer, performing a first annealing on the nitride semiconductor layer at a first temperature within an atmosphere of a nitrogen atom containing gas without providing a protective film on the nitride semiconductor layer, forming the protective film on the nitride semiconductor layer after the first annealing, and after the protective film is formed, performing a second annealing on the nitride semiconductor layer at a second temperature that is higher than the first temperature.