| 摘要 |
A vertical bipolar structure is fabricated utilizing high energy implant techniques. An epitaxial substrate (10) is first formed of the first conductivity material. A deep implant is formed in the substrate to a first level to form a layer (12) of the first conductivity type. Thereafter, a second implant at a slightly lower energy level is made to provide a second conductivity type layer (14) on top of the layer (12). A third implant of a lower energy of the first conductivity type material is then made to form an even shallower depth layer (16). This is followed by a final lower energy implant to form a second conductivity type layer (18) above the layer (16). This therefore results in vertical stack of alternating conductivity type layers. The substrate is then patterned and etched to form vertical structures (26) which are disposed in an array with trenches aligned along the columns and the rows. An insulating material is then disposed in the trenches and a portion of the insulating layer proximate to the sidewalls of one of the rows of trenches etched downward to expose the second layer proximate to the deepest layer and then a layer of polysilicon (36) disposed and etched to form buried contacts (32) to the layer (14).
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