Insulated-gate bipolar transistor (IGBT), chip and method of fabricating the same

An insulated gate bipolar transistor (IGBT) includes: a semiconductor substrate having a top surface extending in a horizontal plane; a three-dimensional (3D) isolation region comprising a silicon compound, the 3D isolation region having a bottom portion and a sidewall portion; a collector region of a first conductive type disposed on the 3D isolation region; a buffer region of a second conductive type opposite to the first conductive type disposed on the collector region; a drift region of the second conductive type disposed on the buffer region; a body region of the first conductive type disposed in the drift region; and at least one source region of the second conductive type disposed in the body region. The 3D isolation region and the top surface of the semiconductor substrate enclose the collector region, the buffer region, the drift region, the body region, and the at least one source region.