A process for forming n- and p-wells in a semiconductor substrate wherein each well has a shallow, highly-doped surface layer whose depth may be independently controlled. This high/low doping profile for a twin well CMOS process may be produced using only one mask level. The method provides high/low...http://www.google.de/patents/US4889825?utm_source=gb-gplus-sharePatent US4889825 - High/low doping profile for twin well process
