Patent ID: 6610572
Filing Date: 2003-08-26
Classification: H01L

Abstract:
A method for manufacturing a semiconductor device from a first-conductivity-type low impurity concentration floating zone (FZ) substrate to form a first-conductivity-type low impurity concentration drift layer, and which comprises an element active region and a first electrode thereof formed at a first principal side of said substrate, a second-conductivity-type high impurity concentration layer and a second electrode thereof formed at a second principal side of said substrate, and a first-conductivity-type high impurity concentration buffer layer formed between said drift layer and said second-conductivity-type high impurity concentration layer, said method comprising the steps of:forming said element active region and said first electrode at said first principal side of said substrate and treating said second principal side of said substrate to reduce it to a predetermined thickness; implanting donor impurity ions from said second principal side and performing an annealing process of irradiating energy to said second principal side, while cooling said first principal side, to thereby form said buffer layer; and implanting acceptor impurity ions from said second principal side and performing an annealing process to thereby form said second-conductivity-type high impurity concentration layer.