The application relates to the technical field of
semiconductor manufacturing, in particular to a
semiconductor device and a preparation method thereof, which comprises a
semiconductor substrate, a first
transistor and a second
transistor, the first
transistor and the second transistor are sequentially arranged above the semiconductor substrate along the thickness direction of the semiconductor substrate from bottom to top, the first transistor comprises a first
gate stack structure and a first source / drain region located on both sides of the first
gate stack structure, the second transistor comprises a second
gate stack structure and a
second source / drain region located on both sides of the second gate stack structure, a gate isolation structure is arranged between the first gate stack structure and the second gate stack structure, and a source / drain isolation region is arranged between the first source / drain region and the
second source / drain region; wherein, in the width direction of the channel, the width of the gate isolation structure and the width of the source / drain isolation region are the same; and the first source / drain region and the
second source / drain region are respectively located below and above the source / drain isolation region. The application significantly reduces the
process integration difficulty of the device.