US Patent 7326953 Layer sequence for Gunn diode

The invention relates to a layered construction for a Gunn diode. The layered construction comprises a series of stacked layers consisting of a first highly doped nd GaAs layer (3), a graded AlGaAs layer (5), which is placed upon the first highly doped layer (3), whereby the aluminum concentration of this layer, starting from the boundary surface to the first nd GaAs layer (3), decreases toward the opposite boundary surface of the AlGaAs layer (5), and of a second highly doped n+ layer (7). An undoped intermediate layer (4, 6) serving as a diffusion or segregation stop layer is placed on at least one boundary surface of the AlGaAs layer (5) to one of the highly doped layers (3, 7) and prevents an unwanted doping of the graded layer.