The invention discloses a variable-width negative
capacitance layer double-gate fin type
field effect transistor and a preparation method thereof. The variable-width negative
capacitance layer double-gate fin type
field effect transistor comprises a
semiconductor substrate, a
buried oxide layer, a fin type active region, a
gate oxide layer, a variable-width negative
capacitance layer, an isolation
oxide layer, a
metal gate and a side wall, the fin type active region comprises a source region, a channel region and a drain region which are sequentially arranged along the length direction; the variable-width negative capacitance layer is symmetrically arranged outside the
gate oxide layer, and the widths of the two ends of the variable-width negative capacitance layer are unequal. The two sides of the
gate oxide layer are covered with the negative capacitance layer with the width changing along the channel, and the
gate voltage is variably amplified and then applied to the two sides of the gate
oxide layer by means of the variable
voltage amplification effect and the gate-drain
coupling effect of the variable width negative capacitance layer, so that the channel control capacity of the
fin field effect transistor is improved, and the reliability of the
fin field effect transistor is improved. The
subthreshold swing of the
transistor is reduced, the saturation region current of the transistor is improved, and the common negative differential resistance phenomenon in the negative capacitance
field effect transistor is weakened, so that the
power consumption of the transistor is reduced, and the performance of the transistor and the performance in a logic circuit are improved.