Yes, it is possible that carbon and silicone-based life forms can be fused together, because this is already being done with modern medicine. Prosthetic limbs for amputees, as well as artificial hearts, already combine the human body with the things that technology can do. As science progresses, eventually there will be complete fusion between these two things.
It is not possible with our knowledge now that Carbon and Silicon based life forms could be fused together. Silicon does not have the ability to connect with other diverse atoms for chemical versatility required in metabolism like Carbon does. Silicon also has difficulty forming dual bonds. It is very unlikely based on our knowledge of biochemistry that these life forms could be fused together.