Semiconductor Device Diamond Heat Dissipation Layer Cracking Prevention
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Solution Overview
Problem
High-frequency semiconductor devices using diamond for heat dissipation often experience cracking due to the significant difference in linear expansion coefficients between diamond and crystalline nitride layers, leading to reduced performance and reliability.
Innovation Solution
A semiconductor device design featuring a layered body with a composite silicon layer that includes non-inhibiting and inhibiting regions, where diamond is grown only on the non-inhibiting regions and separated from the inhibiting regions by voids, relieving stress and preventing cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If diamond is used for heat dissipation in high-frequency devices, then heat dissipation performance is improved, but cracking occurs in the crystalline nitride layer due to thermal expansion mismatch
Solution Approach 1:
The patent applies local quality by creating a composite layer with spatially varying properties: an amorphous silicon region that promotes diamond growth and a crystalline silicon region that inhibits diamond growth. This local differentiation allows diamond to be grown only in specific areas where thermal management is needed, while avoiding regions where thermal expansion mismatch would cause cracking in the crystalline nitride layer.
Solution Approach 2:
The patent uses an amorphous silicon layer as an intermediary between the diamond heat dissipation layer and the crystalline nitride layer. This intermediary layer with intermediate thermal expansion properties buffers the stress caused by the large thermal expansion mismatch between diamond and crystalline nitride, preventing crack propagation while maintaining effective heat dissipation.
2Temperature
If diamond is grown on the entire surface, then heat dissipation is maximized, but stress concentration increases leading to cracking
Solution Approach 1:
The patent implements local quality by restricting diamond growth to only the amorphous silicon region while intentionally leaving the crystalline silicon region without diamond. This selective localization of diamond growth maximizes heat dissipation in critical areas while avoiding stress concentration in regions where diamond presence would compromise structural integrity.
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 voids between the diamond heat dissipation layer and the crystalline nitride layer effectively reduce stress, suppressing cracking and enhancing the heat dissipation performance of the semiconductor device while maintaining structural integrity.
Implementation Method 1
a stress caused by great difference between the linear expansion coefficient of the heat dissipation layer made of diamond and that of the crystalline nitride layer is relieved by the void
Implementation Method 2
The composite layer includes a non-inhibiting portion which does not inhibit diamond growth on a surface thereof and an inhibiting portion which inhibits the diamond growth on the surface
Data Source
AI summary
In a semiconductor device including a crystalline nitride layer, in which diamond is used for heat dissipation thereof, it is an object of the present invention to suppress cracking of the crystalline nitride layer. The semiconductor device includes a layered body and a heat dissipation layer. The layered body includes a crystalline nitride layer and a composite layer. The composite layer includes a non-inhibiting portion which does not inhibit diamond growth on a surface thereof and an inhibiting portion which inhibits the diamond growth on the surface. A layered body main surface of the layered body has a first region in which the non-inhibiting portion is exposed and a second region in which the inhibiting portion is exposed. The heat dissipation layer is made of diamond, opposed to the main surface, adhered to the first region, and separated from the second region with a void interposed therebetween.