A manufacturing method for semiconductor device includes: forming an opening, in a surface of a semiconductor substrate being composed of first atom, the opening having an opening ratio y to an area of the surface of the semiconductor substrate ranging from 5 to 30%; forming an epitaxial layer in the opening, the epitaxial layer being made of a mixed crystal containing a second atom in a concentration ranging from 15 to 25%, and the second atom having a lattice constant different from a lattice constant of the first atom; implanting impurity ion into the epitaxial layer; and performing activation annealing at a predetermined temperature T, the predetermined temperature T being equal to or higher than 1150° C. and satisfies a relationship of y≦1E-5exp(21541/T).