When Nd doping in BiNdFeO (BNFO) film exceeds 10%, the two diffraction peaks (104)/(110) merge into one sharp single peak with increasing the addition of Nd. It seems that a phase structural distortion can be obtained due to the substitution of Nd3+ ion for Bi3+ ion. For ferroelectric properties, among all Nd-doped (0-20%) BiFeO3 capacitors, the BNFO capacitor with 10% Nd doping shows a higher Pr value due to a phase structural distortion and a lower leakage current. In a resistive-capacitive circuit diagram, the transient response of the voltage (VFE) across the BNFO capacitor can be measured. We demonstrate that the capacitance value ((dQ(t))/(dV_FE (t))) is negative in the spike interval of VFE(t), such that the negative capacitance of BNFO with 10% Nd doping capacitor can obviously improve the IDS–VGS characteristics of control thin film transistor.