High-voltage metal oxide semiconductor device and method of forming the device

摘要

A method of forming a high-voltage metal oxide semiconductor device (MOS) includes forming a device with a high voltage support region 44 of n-type silicon. The voltage support region 44 has between 5x1015 and 2x1016 impurity atoms/cm3, for example phosphorous ions, in a first well 14 directly below a drift region 17. The voltage support region 44 is formed using ion implantation and a resist mask. The MOS device has a substrate 10 of p type silicon which has between 5x1019 and 1.3 x 1020 impurity atoms/cm3. An epitaxial layer of p type silicon 12 which has between 1x1015 and 3x1015 impurity atoms/cm3 is formed on the substrate 10. The first well 14 of n type silicon which has between 1x1016 and 4x1016 impurity atoms/cm3 is formed in the epitaxial layer 12. First well 14 has a first channel region 11 which is formed using ion implantation and a resist mask. The drift region 17 of p type silicon which has between 3x1016 and 7x1016 impurity atoms/cm3, for example boron ions, is formed in the first well 14 using ion implantation and a resist mask. The MOS device also includes a first source 16 and drain 18 of p type silicon which have 5x1019 and 2x1020 impurity atoms/cm3. The first source 16 and drain 18 are formed in the first well 14 using ion implantation and a resist mask. Preferably, the high voltage support region 44 avoids punch-through from the p channel drain 18 through the drift region 17 into the substrate 10 while using a standard depth for the n type well 14. The high voltage device may be integrated with a standard n or p channel device on the same chip or wafer.