Highly robust 1700V diodes fabricated on 8" line using optimized proton implanted buffer

Migrating high power device production from 6 to 8 wafers can significantly reduce unit cost. However, for 1700V freewheeling diodes, it is not practical to continue using the diffused buffer on 8 wafer production line as it has been the norm for 6 wafer production line. This is because much thicker starting wafers are typically used in 8 production line for frontside processing due to the requirement of mechanic stability. Therefore, very large thermal budget would be required to produce a very deep buffer for 8 wafer, leading to significant wafer bow, breakage and cost. Therefore an alternative method of producing sufficiently strong buffer has to be found.