Patent ID: 8158484

Claim:
A method of forming an inverted T shaped channel structure having a vertical channel portion and a horizontal channel portion at a bottom of the vertical channel portion for an Inverted T channel Field Effect Transistor ITFET device, the method comprising: providing a semiconductor substrate; providing a first layer of a first semiconductor material over the semiconductor substrate; providing a second layer of a second semiconductor material over the first layer; etching the first layer and the second layer, the first and the second semiconductor materials being selected such that for same etch conditions the first semiconductor material has an etch rate which is less than an etch rate of the second semiconductor material and an etch rate across the second layer increases as a distance from a junction between the first and second layers increases to a predetermined distance after which the etch rate of the second semiconductor layer is constant, wherein during the etching, portions of the first layer and the second layer are removed selectively according to the different etch rates so as to provide a lateral layer over the semiconductor substrate and the vertical channel portion of the inverted T shaped channel structure with rounded corners at a junction between the vertical channel portion and the lateral layer; and removing a portion of the lateral layer so as to provide the horizontal channel portion of the inverted T shaped channel structure.