Method for manufacturing transistor T-shaped gate

The present invention provides a method for manufacturing a high electron mobility transistor T-shaped gate used for a microwave and millimeter wave integrated circuit. One characteristic of the method is to form the structure of the T-shaped gate by two times of defocusing, thereby enhancing the mechanical strength and reliability of the T-shaped gate. The second characteristic of the method is that a miniaturization step and a thermal deformation step are adopted during the manufacture process, thereby reducing the size of a root cavity of the T-shaped gate, and manufacturing the T-shaped gate having a smaller gate length.