MTBF is not an appropriate metric for semiconductors as they are not
repairable. MTBF is more of a system level question. However MTTF (MTTF equals
MTBF with a repair time of zero) is appropriate and this is freely available
from analogs external website.
html selecting wafer fabrication data and then selecting the product provides
MTTF and FIT data. The calculator also allows customers to select any
temperature they wish for the calculation.