Delivery of final Si/SiC material for test device structures. Communication of interim physical characterisation informing WP3

Development of Si/SiC bonding trials, refining historic TNI-UoW trials for 100mm and 150mm wafer coverage. This task will involve SiC-to-Si wafer bonding (WB) process development and optimization of bonding parameters including radical activation using remote plasma for the purpose of transferring a thin Si film onto a SiC wafer. The wafers will be bonded under vacuum (10–5 mbar) and exposed to free radicals generated by a remote plasma ring prior to wafer-to-wafer contact. Wafers will then be bonded under a force while being annealed in-situ. Post bonding Si wafer to SiC wafer, Si substrate will be thinned down to a couple of microns. In case of using SOI, the whole Si substrate will be removed. In either case, the substrate thinning will start with grinding followed by chemical etching. The greatest challenge here will be the bond strength which should tolerate the mechanical stress during mechanical grinding/polishing. Results obtained at this stage will be fed to Task 3.2 for bonding process modification accordingly to increase the bond strength. Depending on the bond strength (go/no go decision making point), we may develop annealing step, micro-channel formation and/or use an ultrathin interfacial layer to enhance the bond strength. Following this step AFM measurement will be used to define the roughness of the Si film transferred onto SiC wafer after polishing. In the case of SOI wafers, the oxide layer will be removed chemically after grinding the Si substrate.