Bipolar device and manufacturing method thereof

The invention provides a bipolar device and a manufacturing method thereof.The method comprises the steps that an SOI substrate is provided, the SOI substrate comprises top layer silicon, a buried oxide layer and top layer silicon which are sequentially arranged from bottom to top, a plurality of shallow trench isolation structures are formed in the top layer silicon, the horizontal section of each shallow trench isolation structure is in a T shape, and the shallow trench isolation structures are formed in the bottom layer silicon; each shallow trench isolation structure comprises a transverse isolation structure and a longitudinal isolation structure connected with the transverse isolation structure, and an interval region is arranged between every two adjacent shallow trench isolation structures; performing ion implantation to respectively form two bases on two sides of the longitudinal isolation structure; a collector electrode is formed between the transverse isolation structure and the two base electrode