Semiconductor device with power transistor cells and lateral transistors and method of manufacturing

摘要

By thermal oxidation a field oxide layer is formed that lines first and second trenches that extend from a main surface into a semiconductor layer. After the thermal oxidation, field electrodes and trench gate electrodes of power transistor cells are formed in the first and second trenches. A protection cover including a silicon nitride layer is formed that covers a cell area with the first and second trenches. With the protection cover covering the cell area, planar gate electrodes of lateral transistors are formed in a support area of the semiconductor layer.

主权项

1. A method of manufacturing a semiconductor device, the method comprising:
forming, by thermal oxidation, a field oxide layer lining first and second trenches that extend from a main surface into a semiconductor layer; forming, after the thermal oxidation, field electrodes and trench gate electrodes of power transistor cells in the first and second trenches; forming a protection cover comprising a silicon nitride layer and covering a cell area that comprises the first and second trenches; forming, by local oxidation of silicon and after forming the protection cover, insulator structures between the cell area and the support area and/or between areas assigned to lateral transistors; and forming planar gate electrodes of lateral transistors in a support area of the semiconductor layer with the protection cover covering the cell area.