«ALTERPHASiC» technology

Our “ALTERPHASiC” method differs from all other existing ones. We do not grow the film from above, but rather replace silicon atoms with carbon atoms in a special way, retaining the original crystal structure of Si matrix - the so-called nano-assembly method. The method allows us to “convert” a very thin layer of Si to both cubic and hexagonal silicon carbide. At the same time during conversion a special “ALTERPHASiC” porous buffer layer is being formed under the silicon carbide layer.

This combination allows one to detach mechanically the Si substrate from all subsequent layers. It significantly reduces the effect of the difference in CTE and lattice mismatch, and ensures low defect formation during nucleation and growth of GaN and AlN thanks to thin SiC layer. Thus, the ALTERPHASiC substrate “adapts” to the lattice of WBG semiconductors, and provides the possibility to grow almost defect-free nitride layers by any of conventional methods (MBE, CVD, HVPE) without use of superlattices, thick AlGaN buffers or other sophisticated and expensive methods like ELO or pendeo-epitaxy. Use of ALTERPHASiC technology allows one to provide the necessary structural excellence of subsequent III-N layers, and at the same time ensures low cost and time saving during the growth process.

 

Inherent advantages of ALTERPHASiC SiC/Si templates

ALTERPHASiC templates substrates are grown on standard Si wafers of p- and n-type of 1”, 2”, 3”, 4”, 6” size. The films are uniform across the whole surface. Further diameter scale up is ONLY limited with size of currently used reactor chamber and Si substrates diameters available. The films are uniform across the whole surface.

“ALTERPHASiC” substrates are available at 1 to 6 inch sizes.

  • Thick (up to hundreds of microns) and high-quality layers of III-V semiconductor materials can be grown on Alterphasic SiC-on-Si wafers. 
  • No need in thick and complex intermediary buffer to fight lattice mismatch.
  • Grown III-V structures are easy to get etched off thanks to porous “Alterphasic” layer.

 

ALTERPHASiC layer advantage in etching off GaN/AlN/SiC and AlN/SiC layers

  • Thick (up to hundreds of microns) and high-quality layers of III-V semiconductor materials can be grown on ALTERPHASiC SiC-on-Si wafers. 
  • No need in thick and complex intermediary buffer to fight lattice mismatch.
  • Grown III-V structures are easy to get etched off thanks to porous “ALTERPHASiC” layer.

We developed separation method of grown III-V structures from Si substrate by chemical etching of ALTERPHASiC layer. ALTERPHASiC porous structure effectively and fast  (few minutes) allows to separate thin film or heterostructure from Si substrate with no need to use more complicated laser separation or plasma etching.

Our separation method of grown WBG heterostructures from proprietary ALTERPHASiC substrate enables application of this grown structures as free standing or transferred to other substrates. It can also be used as a template for further bulk crystal growth.