We report on a new high‐speed InP‐based InxGa1−xAs Schottky barrier photodiode for infrared detection. The photodiodes were fabricated on bothp‐ andn‐InGaAs epilayers. For this application, Schottky barrier height enhancement on InGaAs has been demonstrated. The photodiodes had responsivities as high as 0.55 A/W and quantum efficiencies of up to 45% in the range of 1.3–1.6 &mgr;m without antireflection coating. The response speed of photodiodes was measured by the impulse response and autocorrelation methods; rise times of 85 ps forp‐InGaAs and 180 ps forn‐InGaAs photodiodes were obtained. Recently, a barrier height enhancement of 0.35 eV was obtained inn‐InGaAs photodiodes, resulting in a great reduction of leakage currents. This would lead to further improvement in the device performance of the photodiodes. Based on measured RC time constants, we estimate the intrinsic response speed to be 12 GHz forn‐InGaAs and 18 GHz forp‐InGaAs photodiodes. These results show that InP‐based InxGa1−xAs Schottky barrier photodiodes can be very useful for high‐speed infrared receivers in fiber‐optic communications.