A semiconductor circuit for reducing flicker noise includes a negative-conductance generator and a body bias voltage supplying circuit. The negative-conductance generator includes a pair of cross-coupled field effect transistors in order to generate negative-conductance, wherein each field effect transistor includes a body. In order to remove flicker noise generated by the pair of the field effect transistors, the body bias voltage supplying circuit supplies a body bias voltage to the body of each of the pair of the field effect transistors so that a forward bias voltage is supplied to the body and source of each of the pair of the field effect transistors. The field effect transistors are preferably NMOS transistors or CMOS transistors. The semiconductor circuit is used in a voltage controlled oscillator (VCO) or a phase-locked loop (PLL).