This is one of the transistor types.
The IGBT is insulated-gate bipolar transistor.
Part Number : 20N60A4D, HGTG20N60A4D
Function : 600V, SMPS Series N-Channel IGBT with Anti-Parallel Hyperfast Diode
Package : TO-247 Type
Manufactures : Fairchild
The 20N60A4D is a MOS gated high voltage switching device combining the best features of MOSFETs and bipolar transistors. This device has the high input impedance of a MOSFET and the low on-state conduction loss of a bipolar transistor. The much lower on-state voltage drop varies only moderately between 25 °C and 150 °C. The IGBT used is the development type TA49339. The diode used in anti-parallel is the development type TA49372.