Stmicroelectronics (Crolles 2) Sas

Fabien Deprat

Alexis Gauthier

Pascal Chevalier

Yves Campidelli

Edoardo Brezza

A method of making a bipolar transistor includes forming a stack of a first, second, third and fourth insulating layers on a substrate. An opening is formed in the stack to reach the substrate. An epitaxial process forms the collector of the transistor on the substrate and selectively etches an annular opening in the third layer. The intrinsic part of the base is then formed by epitaxy on the collector, with the intrinsic part being separated from the third layer by the annular opening. The junction between the collector and the intrinsic part of the base is surrounded by the second layer. The emitter is formed on the intrinsic part and the third layer is removed. A selective deposition of a semiconductor layer on the second layer and in direct contact with the intrinsic part forms the extrinsic part of the base.

Method for manufacturing a bipolar transistor and bipolar transistor capable of being obtained by such a method

A bipolar transistor is supported by a single-crystal silicon substrate including a collector contact region. A cyclical epitaxy process is performed to provide a collector region of a first conductivity type on the collector contact region that is laterally separated from a silicon layer by an air gap. A second epitaxial region forms a base region of a second conductivity type. Deposited semiconductor material forms an emitter region of the first conductivity type. The collector region, base region and emitter region are located within an opening formed in a stack of insulating layers that includes a sacrificial layer. The sacrificial layer is selectively removed to expose a side wall of the base region. Epitaxial growth from the exposed sidewall forms a base contact region.

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Chambery, France

Fabien Deprat