Abstract: A transistor production method includes etching a semiconductor substrate to form at least one upper trench portion, sequentially depositing first and second insulating materials over the substrate and partially removing the second insulating material, etching the substrate to form a lower trench portion, depositing a third insulating material over the substrate, disposing a polycrystalline silicon (pc-Si) material in the trench portions and partially removing such material, depositing a fourth insulating material over the substrate and partially removing the third and fourth insulating materials, removing the second insulating material and disposing another pc-Si material in the upper trench portion, and forming a well and a source on the substrate. A trench power transistor thus produced is also disclosed.

Abstract: A trench power transistor includes a semiconductor body having opposite first and second surfaces, and including at least one active region. Such region includes a trench electrode structure, a well, and a source. The trench electrode structure has an electrode trench recessed from the first surface, and includes first, second, and third insulating layers sequentially disposed over bottom and surrounding walls of the electrode trench, a shield electrode enclosed by the third insulating layer, a fourth insulating layer disposed on the first, second, and third insulating layers, and a gate electrode surrounded by the fourth insulating layer. The second insulating layer made of a nitride material and the fourth insulating layer are different in material. A production method of the transistor is also disclosed.