Method of manufacturing semiconductor device that includes forming junction field effect transistor including recessed gate

A method of manufacturing a semiconductor device that includes a junction field effect transistor, the junction field effect transistor including a semiconductor substrate of a first conductivity type, an epitaxial layer of the first conductivity type formed on the semiconductor substrate, a source region of the first conductivity type formed on a surface of the epitaxial layer, a channel region of the first conductivity type formed in a lower layer of the source region, a pair of trenches formed in the epitaxial layer so as to sandwich the source region therebetween, and a pair of gate regions of a second conductivity type, opposite to the first conductivity type, formed below a bottom of the pair of trenches.