Abstract: Heterojunction structure, also referred to as a heterostructure, of semiconductor material, in particular for a high electron mobility transistor (HEMT), includes a substrate, a stack of at least three buffer layers of a same semiconductor material with a wide bandgap EG1 based on a column-III nitride, namely an unintentionally doped first buffer layer, a second buffer layer, an unintentionally doped third buffer layer, an unintentionally doped intermediate layer, and a barrier layer arranged on the intermediate layer, said barrier layer being of a semiconductor material with a wide bandgap EG2 based on a column-III nitride; the second buffer layer has constant P+ doping throughout some or all of its thickness; and the third buffer layer includes a first region which is unintentionally doped throughout its entire thickness and at least one second region adjacent to said first region with N+ doping surrounding the first region.

Abstract: Heterojunction structure, also referred to as a heterostructure, of semiconductor material, in particular for a high electron mobility transistor (HEMT), includes a substrate, a stack of at least three buffer layers of a same semiconductor material with a wide bandgap EG1 based on a column-III nitride, namely an unintentionally doped first buffer layer, a second buffer layer, an unintentionally doped third buffer layer, an unintentionally doped intermediate layer, and a barrier layer arranged on the intermediate layer, said barrier layer being of a semiconductor material with a wide bandgap EG2 based on a column-III nitride; the second buffer layer has constant P+ doping throughout some or all of its thickness; and the third buffer layer includes a first region which is unintentionally doped throughout its entire thickness and at least one second region adjacent to said first region with N+ doping surrounding the first region.

Abstract: A heterojunction structure of semiconductor material, for a high electron mobility transistor includes a substrate, a buffer layer, arranged on the substrate, of a large bandgap semiconductor material, based on a nitride from column III, where the buffer layer is not intentionally doped with n-type carriers, a barrier layer arranged above the buffer layer, of a large bandgap semiconductor material based on a nitride from column III, where the width of the bandgap of the barrier layer is less than the width of the bandgap of the buffer layer. The heterojunction structure additionally comprises an intentionally doped area, of a material based on a nitride from column III identical to the material of the buffer layer, in a plane parallel to the plane of the substrate and a predefined thickness along a direction orthogonal to the plane of the substrate, where the area is comprised in the buffer layer.

Abstract: A heterojunction structure of semiconductor material, for a high electron mobility transistor includes a substrate, a buffer layer, arranged on the substrate, of a large bandgap semiconductor material, based on a nitride from column III, where the buffer layer is not intentionally doped with n-type carriers, a barrier layer arranged above the buffer layer, of a large bandgap semiconductor material based on a nitride from column III, where the width of the bandgap of the barrier layer is less than the width of the bandgap of the buffer layer. The heterojunction structure additionally comprises an intentionally doped area, of a material based on a nitride from column III identical to the material of the buffer layer, in a plane parallel to the plane of the substrate and a predefined thickness along a direction orthogonal to the plane of the substrate, where the area is comprised in the buffer layer.