Method of manufacturing a silicon carbide epitaxial substrate
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Solution Overview
Problem
Basal plane dislocations in silicon carbide epitaxial substrates move when irradiated with ultraviolet light, potentially decreasing the reliability and yield rate of semiconductor devices during manufacturing.
Innovation Solution
A silicon carbide epitaxial substrate with a 4H polytype and a principal surface inclined at an angle θ from the {0001} plane, where a silicon carbide epitaxial layer is grown with basal plane dislocations that are stabilized by irradiation with ultraviolet light of specific power and wavelength, preventing movement even under subsequent exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If basal plane dislocation is present in silicon carbide epitaxial substrate, then manufacturing process can proceed, but dislocation moves when irradiated with ultraviolet light causing reliability decrease
Solution Approach 1:
The patent applies preliminary action by performing ultraviolet light irradiation before the semiconductor manufacturing process to stabilize basal plane dislocations in advance. This preliminary stabilization prevents dislocation movement during subsequent manufacturing steps that involve ultraviolet light exposure, thereby resolving the reliability issue without affecting the manufacturing process itself.
Solution Approach 2:
The patent implements preliminary anti-action by using ultraviolet light irradiation to create a stabilizing effect on basal plane dislocations before harmful dislocation movement can occur during manufacturing. This pre-applied counteraction neutralizes the potential harm of dislocation movement, allowing the manufacturing process to proceed reliably.
2Reliability
If ultraviolet light irradiation is applied to stabilize dislocation, then reliability improves, but additional process step is required
Solution Approach 1:
The patent applies universality by utilizing ultraviolet light irradiation that serves dual purposes: it is both a standard semiconductor manufacturing process step and a dislocation stabilization treatment. This multi-functionality allows the same ultraviolet light exposure used in manufacturing to simultaneously stabilize dislocations, adding minimal process complexity while improving reliability.
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
The stabilization of basal plane dislocations enhances the reliability of semiconductor devices by preventing dislocation movement during manufacturing processes, thereby improving yield rates.
Implementation Method 1
irradiating the silicon carbide epitaxial layer with an ultraviolet light having a predetermined power and a predetermined wavelength for a predetermined period of time to stabilize the basal plane dislocation
Data Source
AI summary
A method of manufacturing a silicon carbide epitaxial substrate includes: preparing a silicon carbide single-crystal substrate having a polytype of 4H and having a principal surface inclined at an angle θ from a {0001} plane in a <11-20> direction; growing a silicon carbide epitaxial layer on the principal surface having a basal plane dislocation, the basal plane dislocation having a portion extending in a <1-100> direction and a portion extending in a <11-20> direction; and irradiating the silicon carbide epitaxial layer with an ultraviolet light having a predetermined power and a predetermined wavelength for a predetermined period of time to stabilize the basal plane dislocation. After the irradiating, the basal plane dislocation does not move even when the basal plane dislocation is irradiated with an ultraviolet light having a power of 270 mW and a wavelength of 313 nm for 10 seconds.