GaN Heterojunction Structure With Backside Vias for Heat Robustness
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Solution Overview
Problem
Existing nitride semiconductor structures face challenges in achieving high power, high voltage, and high-speed operation while being robust to heat damage and current scaling, with issues such as fragility and non-uniform electric field distribution.
Innovation Solution
A semiconductor structure is designed with a vertical conductive GaN structure laterally surrounded by resistive material, sandwiched between two substrates for protection and heat dissipation, and featuring vias for electrical connections from the backside to enhance stability and heat management, along with epitaxial growth of layers for high-quality heterojunctions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If nitride semiconductor layers are grown on a non-nitride substrate and then released for transfer, then device integration flexibility is improved, but the nitride semiconductor layers become fragile and may break during transfer
Solution Approach 1:
A buffer layer is introduced as an intermediary between the non-nitride substrate and the nitride semiconductor layers. This buffer layer serves as a mediator that allows the nitride layers to be grown on a non-nitride substrate while maintaining their structural integrity, preventing direct contact between the fragile nitride layers and the substrate that would cause breakage during transfer operations.
Solution Approach 2:
The buffer layer provides beforehand cushioning support to the nitride semiconductor layers, preventing them from breaking during the transfer process. By having this protective layer in place before the transfer operation begins, the fragile nitride layers are cushioned against mechanical stresses that would otherwise cause failure during handling and integration.
2Power
If nitride semiconductor layers are operated at high power and voltage, then device performance is improved, but heat generation increases causing thermal damage and structural breakage
Solution Approach 1:
The buffer layer acts as a thermal intermediary between the nitride semiconductor layers and the substrate. It provides a thermal interface that helps manage heat flow, preventing excessive heat accumulation in the nitride layers during high-power operation while maintaining electrical functionality.
Solution Approach 2:
The buffer layer modifies the thermal parameters of the device structure by providing a controlled thermal interface. This changes the heat dissipation characteristics, allowing the device to operate at high power levels without suffering from thermal damage by managing the thermal parameters through the buffer layer's thermal conductivity and interface properties.
3Reliability
If different material layers are used in the semiconductor structure, then functional performance is improved, but differential thermal expansion causes structural breakage
Solution Approach 1:
The buffer layer serves as a compositional intermediary between materials with different thermal expansion coefficients. It provides a gradual transition in material properties, reducing the abrupt differential thermal expansion that would occur at sharp interfaces between dissimilar materials, thereby preventing structural breakage while maintaining functional performance.
Solution Approach 2:
The buffer layer creates a composite structure that combines materials with different properties. This composite approach allows the structure to accommodate differential thermal expansion by distributing thermal stresses across multiple material layers with graded properties, preventing catastrophic failure while maintaining the functional benefits of different materials.
4Speed
If current is scaled down for high-speed operation, then switching speed is improved, but the structure becomes more susceptible to heat damage
Solution Approach 1:
The buffer layer provides a thermal management intermediary that becomes increasingly important as current scales down. Even at lower current levels, the buffer layer ensures efficient heat dissipation pathways are maintained, preventing heat accumulation in the scaled-down structures that would otherwise be more susceptible to thermal damage.
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 structure achieves improved robustness, efficient heat dissipation, and uniform electric field distribution, enabling high power, high voltage, and high-speed operation with reduced risk of breakage and enhanced electron mobility.
Implementation Method 1
epitaxial growth of layers for high-quality heterojunctions
Implementation Method 2
a vertical conductive GaN structure laterally surrounded by resistive material
Implementation Method 3
the heterojunctions described herein may be configured to form a two-dimensional electron gas (2DEG)
Implementation Method 4
efficient heat dissipation
Data Source
Figure 1a
Figure 1b
Figure 1c~1d
AI summary
A semiconductor structure comprising: a first substrate (101); a first layer (102) arranged on a frontside of the first substrate; a second layer (103), the second layer comprising GaN; a third layer (104), the third layer comprising a vertical conductive GaN structure (104a) laterally surrounded by resistive material (104b); a first heterojunction structure (105), the first heterojunction structure comprising a GaN layer and an AlGaN layer; a contact layer (109), the contact layer comprising a gate contact (110) aligned on a same vertical axis as the vertical conductive GaN structure of the third layer; the contact layer comprising a source/drain contact (111); a second substrate (113) bonded to the contact layer; a first via (114) extending from the backside of the first substrate to the gate contact in the contact layer; a second via (115) extending from the backside of the first substrate to the source/drain contact in the contact layer; a third via (116) extending from a backside of the first substrate to a source/drain contact in the second layer.