Mesa Heater Layout With Gap Insulation for Thermal Stress Relief
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing semiconductor devices face issues with characteristic changes or decreases in reliability due to thermal expansion coefficient differences between the mesa portion, heater, and insulator, leading to potential cracks in the heater or electrode when they are arranged across the insulator from the mesa portion.
Innovation Solution
The semiconductor device incorporates a mesa portion with a semiconductor layered structure, extending portions separated by trench grooves, insulating portions made from an insulating material like polyimide, and a conductive portion (heater) arranged on the upper side of the mesa portion. The insulating portions adhere intimately to the mesa portion and form gaps between themselves and the extending portions, while the heater is positioned across the insulating portions and the mesa portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the heater is arranged across the insulator from the mesa portion, then the heater can be positioned to heat the mesa portion effectively, but stress concentrates at the interface between the heater, insulator, and mesa portion due to thermal expansion coefficient differences, leading to cracks and reduced reliability
Solution Approach 1:
The patent introduces an insulating portion as an intermediary element between the heater and the mesa portion. This insulating portion has a thermal expansion coefficient that is intermediate between that of the heater and the mesa portion, acting as a buffer to reduce stress concentration at the interface. The insulating portion is arranged to extend from the mesa portion toward the heater, creating a gradual transition zone that mitigates the thermal expansion mismatch and prevents crack formation while allowing the heater to effectively heat the mesa portion.
2Object-generated harmful factors
If the insulator is filled in the trench groove to provide electrical insulation, then electrical isolation is achieved, but the rigid insulator structure creates stress concentration points at the interfaces with the semiconductor layers, potentially causing cracks
Solution Approach 1:
The patent changes the physical and mechanical parameters of the insulating material by selecting materials with specific properties - particularly those with flexibility and thermal expansion coefficients matched to the surrounding structures. The insulating portions are designed with controlled thickness and elasticity parameters that allow them to accommodate thermal expansion and contraction without creating stress concentration points, thereby maintaining both electrical insulation and interface strength.
3Use of energy by moving object
If the heater is placed directly on the mesa portion to maximize heating efficiency, then thermal coupling is optimized, but the direct contact creates stress concentration due to thermal expansion coefficient differences, leading to heater cracks
Solution Approach 1:
The patent introduces an insulating portion as an intermediary element between the heater and the mesa portion. This insulating portion has a thermal expansion coefficient that is intermediate between that of the heater and the mesa portion, acting as a buffer to reduce stress concentration at the interface. The insulating portion is arranged to extend from the mesa portion toward the heater, creating a gradual transition zone that mitigates the thermal expansion mismatch and prevents crack formation while allowing the heater to effectively heat the mesa portion.
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 configuration suppresses stress on the heater and insulating portions, reducing the likelihood of cracks and thereby maintaining the reliability and characteristics of the semiconductor device.
Implementation Method 1
at least one of the insulating portions adheres intimately to the mesa portion
Implementation Method 2
a conductive portion that is arranged on an upper side of the mesa portion
Data Source
AI summary
A semiconductor device includes: a mesa portion that has a semiconductor layered structure, and that extends in a predetermined direction; an extending portion that extends along the mesa portion and that is separated by trench grooves arranged respectively on both sides of the mesa portion; insulating portions that are made from an insulating material, and are arranged in the respective trench grooves; and a conductive portion that is arranged on an upper side of the mesa portion. Further, at least one of the insulating portions adheres intimately to the mesa portion, and forms a gap between the at least one of the insulating portions and the extending portion in at least a part of an extending direction of the mesa portion, and the conductive portion is arranged across at least one of the insulating portions and the mesa portion.