Patent ID: 8288230
Filing Date: 2012-10-16
Classification: H01L

Abstract:
1. A method for producing a transistor with a gate electrode structure, the method comprising: providing a semiconductor body with a first surface, and with a first sacrificial layer extending in a vertical direction of the semiconductor body from the first surface, the first sacrificial layer comprising a different material than the semiconductor body which can be removed or etched selectively relative to the semiconductor body; forming a first trench extending from the first surface into the semiconductor body, wherein forming the first trench comprises removing the sacrificial layer in a section adjacent the first surface; forming a second trench by isotropically etching the semiconductor body in the first trench; forming a third trench below the second trench by removing at least a part of the first sacrificial layer below the second trench; forming a dielectric layer which at least covers sidewalls of the third trench and which only covers sidewalls of the second trench; and forming a gate electrode on the dielectric layer in the second trench, the gate electrode and the dielectric layer in the second trench forming the gate electrode structure.