Transistor device having protruding portion from channel portion

A transistor device, comprising:

• a semiconductor material layer, comprising a first conductive portion, a second conductive portion, a channel portion, and a first protruding portion formed integrally, wherein the channel portion is located between the first conductive portion and the second conductive portion, the channel portion has a first boundary, a second boundary, a third boundary, and a fourth boundary, the first boundary is at a junction of the first conductive portion and the channel portion, the second boundary is at a junction of the second conductive portion and the channel portion, the third boundary and the fourth boundary connect terminals of the first boundary and the second boundary, and the first protruding portion is protruded outwardly from the third boundary of the channel portion, wherein the semiconductor material layer further comprises a second protruding portion, and the channel portion is located between the first protruding portion and the second protruding portion;
• a gate layer extended across and overlapped with the channel portion, wherein a first gate boundary and a second gate boundary of the gate layer are overlapped with the first boundary and the second boundary of the channel portion;
• and
• an insulating layer disposed between the gate layer and the semiconductor material layer.