Electrical and interface state properties of the borontrifluoride doped poly(3‐aminoacetophenone)/p‐Si junction have been investigated by current‐voltage and impedance spectroscopy methods. Al/p‐Si/P3APBF3/Aldiode indicates a nonideal behavior with electrical parameters (n = 3.53, ϕB = 0.82 eV, and Rs = 1.48 kΩ), which result from the interfacial layer, series resistance, and resistance of the organic semiconductor. The obtained barrier height value of the Al/p‐Si/P3APBF3/Aldiode is higher than that of the conventional Al/p‐Si (ϕB = 0.58 eV) Schottky diode. The interface state density of the diode was of the order of 1.05× 1012 eV−1 cm−2. It is evaluated that the barrier height and interface state density values of the diode are modified using the boron trifluoride doped poly (3‐aminoacetophenone) organic semiconductor. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers