Power device and method of manufacturing the same

A method of manufacturing a power device, the method comprising:

• performing a first ion implant process by implanting impurity ions of a first conductive type into a front surface of a semiconductor substrate to form an implanted first field stop layer, the semiconductor substrate being the first conductive type;
• performing a second ion implant process by implanting impurity ions of the first conductive type into a first part of the implanted first field stop layer such that an impurity concentration of the first part of the implanted first field stop layer is higher than an impurity concentration of a second part of the implanted first field stop layer;
• forming a drift region by growing an epitaxial layer having an impurity concentration that is lower than the semiconductor substrate on the implanted first field stop layer;
• forming a plurality of power device cells on the drift region;
• forming a second field stop layer by grinding a rear surface opposite to the front surface of the semiconductor substrate;
• and
• forming a collector region below the second field stop layer.