Semiconductor transistor and manufacturing method thereof

The patent application of the invention is a divisional application of 202111538504.5, and discloses a semiconductor transistor which is characterized in that an ion implantation region with a groove is arranged in a source region and/or a drain region of a semiconductor epitaxial layer; ohmic metal is arranged on the ion implantation region, and ohmic contact is formed between the ohmic metal and the non-groove region part of the ion implantation region and between the ohmic metal and the side wall and the bottom of the groove of the ion implantation region. The cross sectional area of the groove is greater than or equal to half of the cross sectional area of the ohmic metal; the depth of the groove is smaller than the depth of the ion implantation region, and the ohmic metal can be in contact with the surface of the ion implantation region and can also be in contact with the side wall of the groove through the groove formed in the ion implantation region, so that the contact area of the ohmic metal and the