本发明涉及一种带有多个外延层的横向PNP双极晶体管，具体是指利用相同导电类型的多外延层，制备带有深发射极和深集电极区的横向双极晶体管。无需使用沟槽，就能制备深发射极和深集电极区。在每个外延层中，制备垂直对准的扩散区，使扩散区在退火后，合并到连续的扩散区中，作为发射极或集电极或隔离结构。在另一个实施例中，利用沟槽发射极和沟槽集电极区，制备横向沟槽PNP双极晶体管。在另一个实施例中，制备合并了LDMOS晶体管的横向PNP双极晶体管，以获得高性能。

A lateral bipolar transistor with deep emitter and deep collector regions is formed using multiple epitaxial layers of the same conductivity type. Deep emitter and deep collector regions are formed without the use of trenches. Vertically aligned diffusion regions are formed in each epitaxial layer so that the diffusion regions merged into a contiguous diffusion region after annealing to function as emitter or collector or isolation structures. In another embodiment, a lateral trench PNP bipolar transistor is formed using trench emitter and trench collector regions. In yet another embodiment, a lateral PNP bipolar transistor with a merged LDMOS transistor is formed to achieve high performance.