The invention relates to a highly integrated
transistor which comprises a columnar
trunk structure located on a substrate and one or more
branch structures epitaxially growing on the columnar
trunk structure. The columnar
trunk and the
branch structures form a tree-shaped structure; and a
transistor is formed by a single
branch structure or a plurality of branch structures. The substrate area occupied by an existing common
transistor is 2.8 mu m < 2 > (the width is 1.14 mu m and the length is 2.44 mu m), and based on the transistor, under the same area, the integration level can be improved to 144 at least (four tree structures and 36 branches of each
tree structure), and the integration level is continuously improved by changing the distance and the number of branch
layers of the tree structures. Based on the integration level and device arrangement optimization, additional wiring is not needed, and the spatial
layout of connection of different devices in the 3D space can be realized. The ring gate
field effect transistor is manufactured through the
branch structure, the manufacturing steps and difficulties of the ring gate
field effect transistor are reduced, and the phenomenon that the transistor manufactured by a single III-V group material is too obvious in advantages and disadvantages and poor in comprehensive performance is solved.