US Patent 7544545 Trench polysilicon diode

Embodiments of the present invention include a method of manufacturing a trench polysilicon diode. The method includes forming a N−(P−) type epitaxial region on a N+(P+) type substrate and forming a trench in the N−(P−) type epitaxial region. The method further includes forming a insulating layer in the trench and filling the trench with polysilicon forming a top surface of the trench. The method further includes forming P+(N+) type doped polysilicon region and N+(P+) type doped polysilicon region in the trench and forming a diode in the trench wherein a portion of the diode is lower than the top surface of the trench.