Metal oxide semiconductor transistor and fabrication method thereof

A metal oxide semiconductor transistor comprising a first doping type substrate, an isolation layer, a plurality of gates, a masking layer, a gate oxide layer, a plurality of second doping type source/drain regions and spacers. The first doping type substrate has a plurality of trenches patterning out a plurality of first doping type strips. The isolation layer is disposed within the trenches. The gates is disposed over the first doping type strips and oriented in a direction perpendicular to the first doping type strips. The masking layer is disposed over the first doping type substrate. The gate oxide layer is disposed between the sidewall of the first doping type strips and the gate. The second doping type source/drain regions are disposed in the first doping type strip on each side of the gate. The spacers are disposed on the sidewalls of the gates and the first doping type strips.