Semiconductor device

The purpose of the present invention is to provide a semiconductor device capable of independently controlling the operation of a pnp region and the operation of a pn region. A semiconductor device according to the present invention has a laminated structure comprising: an n-type n-i layer (3); a p-type p anode layer (4) formed on the surface of the n-i layer (3); an n-type n-buffer layer (7) formed on the back surface of the n-i layer (3); an n-type n + cathode layer (5) and a p-type p collector layer (6) which are formed on the back surface of the n-buffer layer (7) or the back surfaces of the n-i layer (3) and the n-buffer layer (7) so as to be adjacent to each other or so as to partially overlap each other in plan view; a surface electrode (8) formed so as to cover the surface of the p anode layer (4); and a rear surface electrode (9) that is formed so as to cover the rear surfaces of the n + cathode layer (5) and the p collector layer (6), and the stacking height position of the n + cathode layer (5) in