Diamond-Assisted SiC Substrates for GaN-HEMT Heat Dissipation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current semiconductor devices, particularly GaN HEMTs, face significant heat dissipation challenges due to low thermal conductivity materials, leading to reduced efficiency and stability as device frequency and integration increase, with existing high thermal conductivity materials like diamond being costly and difficult to produce.
Innovation Solution
A direct growth method is developed to create diamond-assisted heat dissipation silicon carbide substrates for GaN HEMTs, involving laser etching, ultrasonic cleaning, spin-coating of nano-diamond suspension, and microwave plasma-assisted chemical vapor deposition to deposit diamond layers within etched holes in SiC wafers, enhancing thermal conductivity and compatibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If diamond is used as heat-dissipation material for GaN-HEMTs, then thermal conductivity is improved (up to 2200 W/(m·K)), but production cost increases and manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by depositing diamond material only in specific regions where heat dissipation is most critical. The diamond-containing suspension is selectively applied to create localized high thermal conductivity zones rather than uniformly treating the entire substrate, optimizing both thermal performance and manufacturing cost.
Solution Approach 2:
The patent uses composite materials by combining diamond particles with a suspension medium that can be applied to the SiC substrate. This creates a composite structure where diamond provides exceptional thermal conductivity while the suspension matrix enables cost-effective application through existing coating techniques, avoiding the need for pure diamond fabrication.
2Temperature
If diamond is used as heat-dissipation material for GaN-HEMTs, then thermal conductivity is improved (up to 2200 W/(m·K)), but manufacturing process complexity increases and existing production lines must be abandoned
Solution Approach 1:
The patent achieves universality by designing a process that can be integrated into existing SiC production lines. The suspension coating method uses equipment and processes already available in standard semiconductor manufacturing, allowing the heat dissipation enhancement to be added without requiring completely new production infrastructure.
Solution Approach 2:
The patent applies preliminary action by pre-dispersing diamond particles in a suspension medium before application. This preparation step enables the diamond material to be easily applied using standard coating techniques, simplifying the overall manufacturing process compared to attempting to deposit solid diamond directly or grow it in situ.
3Ease of manufacture
If SiC substrate is used for GaN-HEMTs, then compatibility with existing production lines is maintained, but thermal conductivity is insufficient (only about 400 W/(m·K))
Solution Approach 1:
The patent creates a composite structure by incorporating diamond particles into the SiC substrate system. The diamond-SiC composite maintains the substrate's compatibility with existing production lines while adding the exceptional thermal conductivity of diamond, achieving both manufacturing feasibility and improved heat dissipation.
Solution Approach 2:
The patent applies local quality by enhancing thermal conductivity only in specific regions of the SiC substrate where heat dissipation is most needed. This localized enhancement preserves the overall SiC substrate structure and its manufacturing advantages while providing targeted thermal performance improvement.
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 method improves heat dissipation performance by achieving high thermal conductivity (up to 1400 W/(m·K) for the diamond, allowing efficient heat guidance from hot spots while maintaining compatibility with existing production lines without the need for new infrastructure.
Implementation Method 1
Etching holes on a surface of a SiC substrate by laser etching
Implementation Method 2
Placing the SiC wafer containing the hole structure sequentially in anhydrous ethanol and deionized water for ultrasonic cleaning
Implementation Method 3
Spin-coating a nano-diamond suspension on a surface of the cleaned SiC wafer containing the hole structure
Implementation Method 4
Placing the SiC wafer with the establishment of the auxiliary nucleation point in a microwave plasma-assisted chemical vapor deposition (MPCVD) device to deposit a diamond layer
Implementation Method 5
microwave plasma-assisted chemical vapor deposition
Implementation Method 6
microwave plasma-assisted chemical vapor deposition
Implementation Method 7
Polishing the SiC wafer with the diamond nucleation film layer to remove the diamond nucleation film layer on an upper surface
Data Source
AI summary
Direct growth methods for preparing diamond-assisted heat-dissipation silicon carbide substrates of GaN-HEMTs are disclosed. In an embodiment, the direct growth method includes the following steps: (1) etching holes in a surface of a silicon carbide substrate to produce a silicon carbide wafer; (2) ultrasonic cleaning the produced silicon carbide wafer; (3) establishing an auxiliary nucleation point on a surface of the silicon carbide wafer; (4) depositing a diamond layer; (5) removing the portion of the diamond layer on the upper surface while retaining the portion of the diamond layer in the holes; (6) ultrasonic cleaning; and (7) depositing diamond in the holes on the silicon carbide wafer until the holes are fully filled.