MANUFACTURING METHOD OF T-SHAPED GATE Russian patent published in 2017 - IPC H01L21/28 

FIELD: electricity.

SUBSTANCE: essence of manufacturing short T-shaped gates with a high aspect ratio and a gentle incline of the stem walls with the help of a dielectric mask consists in the sequential deposition of a two-layer dielectric SiO₂/SiN_x, etching of a gap in the upper dielectric SiN_x with time control or up to the stop layer, conformal deposition of a thin layer of dielectric Al₂O₃, etching it with the dimensions of the gaps corresponding to the gate length, and further etching of the lower layer of SiO₂ through the obtained mask of Al₂O₃. After this, the residues of Al₂O₃, overhanging the gap in the lower layer of SiO₂, are removed by dry etching in a chlorine-containing gas (BCl₃). The last operation, depending on the plasma exposure time, can create a gate recessing to bring the gate into proximity with channel area of the transistor, if necessary.

EFFECT: improved characteristics of the transistor, inter alia, increased breakdown voltage, reduced effect of traps in the gate area, reduced current collapse, and reduced gate-drain capacity.

5 cl, 10 dwg