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The device under investigation is a Double Base Silicon Bipolar Junction
Transistor epitaxially grown by a Chemical Vapor Deposition (CVD) process. An
n-well (Arsenic), similar to the implanted one used in the standard CMOS
technology, is grown during the epitaxial process. The buried layer (Antimony)
is connected to a sinker (Phosphorus) to conduct the electron current from the
buried layer to the collector contact.
The base consists of an intrinsic base (below the emitter window, Boron-doped)
and the extrinsic base (highly Boron-doped under the base contact).
The emitter-base junction is formed by a diffusion process of a polysilicon
layer which is placed on the p-doped base under the emitter window. After
implantation of Arsenic, a diffusion process pushes the Arsenic into the
p-doped base, thus forming the emitter-base junction.