Considering that the B field will force the electrons on twisted paths, and given that the function of semiconductor devices is based on low charge carrier density and high velocity (compared to metals), and intricate diffusion phenomena, there's plenty of potentially weak spots to fall victim to the field. In short, the carriers will Hall effect all over the place and create compenasating static E fields -- it'll be interesting.
My gut feeling is: bipolars won't notice, FETs will quit. Think about operating an eletron tube in a B field. OK, that's too far-fetched.
When you do the experiments, tell us about the results.
robert