Compound semiconductor device and method for fabricating

摘要

A first GaN layer, a first AlGaN layer, a second GaN layer and a third GaN layer are formed in layers on a substrate. A second AlGaN layer is formed on the sidewall of an opening formed in the multilayer structure. A gate electrode is formed to fill an electrode trench in an insulating film. A portion of the insulating film between the gate electrode and the second AlGaN layer functions as a gate insulating film. A source electrode is formed above the gate electrode and a drain electrode is formed below the gate electrode. This configuration enables implementation of a miniatuarizable, reliable vertical HEMT that has a sufficiently high withstand voltage and high output power and is capable of a normally-off operation without problems that could otherwise result from the use of a p-type compound semiconductor.

主权项

1. A method for fabricating a compound semiconductor device, the method comprising:
forming a first compound semiconductor, a second compound semiconductor that has a lattice constant smaller than the lattice constant of the first compound semiconductor, and a third compound semiconductor that has a lattice constant greater than the lattice constant of the second compound semiconductor, on a surface of a substrate, in such a manner that the first, second and third compound semiconductors have an opening; forming a fourth compound semiconductor in contact with a whole side surface which is an inner wall of the opening, the fourth compound semiconductor having a lattice constant smaller than the lattice constants of the first compound semiconductor and the third compound semiconductor; forming an insulating film to cover the inner wall surface of the opening; forming a gate electrode to fill the opening lined with the insulating film; and forming a first electrode below the first compound semiconductor and forming a second electrode above the third compound semiconductor, wherein a two-dimensional electron gas is produced in a vertical direction to the surface of the substrate at an interface of the first compound semiconductor with the fourth compound semiconductor and at an interface of the third compound semiconductor with the fourth compound semiconductor.