OPTIMIZED BUFFER LAYER FOR HIGH MOBILITY FIELD-EFFECT TRANSISTOR

摘要

The invention relates to a stack (10) along a Z-axis for a high electron mobility field-effect transistor comprising: a buffer layer (12) comprising a first semiconductor material comprising a binary or ternary or quaternary nitride compound and having a first band gap, a barrier layer (13) comprising a second semiconductor material comprising a binary or ternary or quaternary nitride compound and having a second band gap, said second band gap being greater than the first band gap, a heterojunction (15) between said buffer layer (12) and said barrier layer (13) and a two-dimensional electron gas (9) located along an XY plane perpendicular to the Z-axis and adjacent to the heterojunction (15), characterized in that: said buffer layer (12) comprises an area (Vf) having fixed negative charges (70) with a volume density ([Fv]) no lower than 1017 cm-3, the thickness (t) of said area (Vf) being no higher than 200 nm, the product of the volume density of the fixed negative charges ([Fv]) by the thickness (t) of the area (Vf) being between 1012 cm-2 and 3.1013 cm-2.