Planar pseudomorphic InGaAs Schottky diodes with current transport along the 2-DEG channel were prepared and their DC properties are described. The I–V behaviour is similar to diodes without 2-DEG (n = 1.12 ΦB = 0.49 eV), but the C–V characteristics show stronger capacitance variation. On double-barrier 2-DEG Schottky diodes the capacitance ratio Cmax/Cmin = 42 and the varactor sensitivity S(1 V) = 3.75 are obtained and for optimised devices an RC cutoff frequency higher than 2 THz is expected.