Method for forming high quality oxide layers of different thickness in one processing step

The present invention relates to a method for forming high quality oxide layers of different thickness over a first and a second semiconductor region in one processing step. The method comprises the steps of: doping the first and the second semiconductor region with a different dopant concentration, and oxidising, during the same processing step, both the first and the second semiconductor region under a temperature between 500° C. and 700° C., preferably between 500° C. and 650° C. A corresponding device is also provided. Using a low-temperature oxidation in combination with high doping levels results in an unexpected oxidation rate increase.