The invention provides a self-aligned two-dimensional
crystal material field-effect
semiconductor device and a preparation method thereof, and belongs to the technical field of
semiconductor devices. The
semiconductor device provided by the invention comprises a gate
electrode region, a source
electrode region, a drain
electrode region and a two-dimensional
crystal material layer, wherein the two-dimensional
crystal material layer is connected with a source electrode and a drain electrode, and strides the local part of the gate electrode region; and a
gate dielectric oxidation layer is arranged between the two-dimensional crystal material layer and the gate electrode region at the lower part of the two-dimensional crystal material layer. By a self-aligned technology provided by the invention, position alignment of the gate electrode and the source electrode and the drain electrode of the device can be automatically achieved, so that, on one hand, the coverage
capacitance of the gate electrode, the source electrode and the drain electrode is greatly reduced, which has important significance for improvement of the working frequency of the device; and on the other hand, the self-aligned device structure with the gate electrode, the source electrode and the drain electrode greatly reduces channel
layers, namely the parasitic resistance of the two-dimensional crystal material, between the gate electrode and the source electrode and between the gate electrode and the drain electrode, which is also beneficial to improvement of the working frequency of the device.