Drain extended MOS transistor and method for fabricating the same

摘要

A drain extended MOS (DEMOS) transistor including at least one of: (1) A p-type epitaxial layer grown over an n-type semiconductor substrate. (2) An n-type well formed in a portion of the epitaxial layer. (3) A p-type drift region formed in another portion of the epitaxial layer. (4) A p-type source region formed in the well. (5) A p-type drain region formed in the drift region and spaced apart from the source region inside the epitaxial layer. (6) An n-type channel region extending between the drift region and the source region. (7) A gate structure formed over the channel region. (8) An n-type buried layer having a contact surface with the well and the drift region and formed in the epitaxial layer. A region of the buried layer has surface contact with the drift region and has a relatively low dopant concentration compared to other regions.