The main purpose for depositing metal layers onto Bi2Te3-Sb2Te3 semiconductor dices
1) Creation of the diffusion barrier preventing solder components (especially copper, silver and tin) from penetrating semiconductors dices.
2) Creation of solderable layer over the diffusion barrier in order to protect the diffusion layer from oxidation and to provide an good quality of soldering.
As to diffusion barriers RusTec can propose two variants:
• Chemical deposition of Ni-based multilayers with thickness 7±2 microns,
• For special applications (high temperatures or strong cycles) RusTec LLC is ready to recommend patented H-technology where besides diffusion barrier made from Ni-based alloys the thick layer (about 150 microns) of Aluminum is introduced in multilayer structure.
Advantages of modules assembled from dices fabricated by H-technology are represented below.