Wettable Backing Plate for Stable Ga Sputtering
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Solution Overview
Problem
Conventional sputtering deposition methods for Group III nitride compound semiconductors, particularly GaN, face instability and contamination issues due to Ga's liquid state during deposition, as existing backing plates are not designed to handle Ga in a liquid state effectively, leading to poor thermal conduction and surface exposure, resulting in uncontrollable deposition and impurity incorporation.
Innovation Solution
A sputtering deposition apparatus with a backing plate featuring a surface made of easily wettable materials such as silicon, carbon, or silicon nitride, which maintains a contact angle of 90° or less with Ga in a liquid state, allowing stable thermal conduction and preventing surface exposure, ensuring uniform Ga distribution and preventing impurity contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional backing plate is used for Ga sputtering, then the deposition process can be performed, but Ga in liquid state causes poor thermal conduction and surface exposure leading to deposition instability and impurity contamination
Solution Approach 1:
The invention changes the material parameter of the backing plate from conventional materials to easily wettable materials (such as tungsten, molybdenum, or their alloys) that have high affinity with liquid Ga. This parameter change ensures that liquid Ga spreads uniformly on the backing plate surface, maintaining stable thermal conduction and preventing surface exposure, thereby eliminating deposition instability and impurity contamination without affecting deposition rate or requiring additional process steps
Solution Approach 2:
The invention uses a backing plate made of easily wettable material that can be readily replaced. The backing plate is designed to be consumable or replaceable, allowing for simple replacement when worn or contaminated. This approach is more economical than developing complex cleaning or maintenance systems, and ensures consistent deposition quality by replacing the backing plate rather than attempting to restore its properties
2Productivity
If Ga is maintained in liquid state for deposition, then deposition rate increases, but thermal conduction becomes unstable and backing plate surface is exposed
Solution Approach 1:
The invention changes the surface energy parameter of the backing plate by selecting easily wettable materials (tungsten, molybdenum, or their alloys) that have high affinity with liquid Ga. This ensures that liquid Ga maintains stable contact with the backing plate surface, providing consistent thermal conduction while preserving high deposition rate. The easy wettability prevents Ga from retracting or exposing the backing plate surface, thus maintaining both productivity and thermal conduction stability
3Ease of manufacture
If conventional backing plate materials are used, then manufacturing is simple, but Ga wettability is poor causing heat conduction failure and deposition control loss
Solution Approach 1:
The invention changes the material composition parameter of the backing plate to easily wettable materials (tungsten, molybdenum, or their alloys). These materials can be manufactured using conventional techniques such as sintering or machining, maintaining ease of manufacture. The key improvement is in the surface interaction parameter - these materials naturally exhibit high wettability with liquid Ga, ensuring reliable heat conduction and deposition control without requiring complex surface treatments or additional manufacturing steps
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 solution enables stable and impurity-free deposition of GaN layers by maintaining Ga in a stable liquid or solid state, improving the crystallinity and purity of the deposited films, and preventing the backing plate material from being sputtered, thus enhancing the production of high-quality Group III nitride compound semiconductors.
Implementation Method 1
allowing stable thermal conduction
Implementation Method 2
the surface which comes into contact with the target material is formed by an easily wettable material having a contact angle to Ga in a liquid state of not more than 90°
Implementation Method 3
a sputtering deposition apparatus including a backing plate for holding a target material containing Ga
Data Source
AI summary
A backing plate for use in a sputtering deposition apparatus being capable of stably holding Ga, and a sputtering deposition apparatus which is equipped with the backing plate are provided. Such a backing plate for use in a sputtering deposition apparatus is a backing plate for holding a target material which contains Ga, and at least a contact surface of which coming into contact with the target material is constituted from an easily wettable material having a contact angle to Ga in a liquid state of not more than 90°.