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Bipolar silicon transistors may be manufactured in a small area with inter-device isolation by the following steps.
English (United States)
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Bipolar Isolation Technique
Bipolar silicon transistors may be manufactured in a small area with inter-
device isolation by the following steps.
The device area outline is first defined using a photoresist to negatively
expose the device area, the subcollector reachthrough contact and the isolation
configuration with the reachthrough to device spacing governed by two times the
lateral diffusion in subsequent processing. This step is illustrated in Fig. 1.
Silicon dioxide is grown on the unmasked areas. The photoresist is
removed, and high conductivity is implanted thereunder. These steps are
illustrated in Fig. 2.
Silicon is grown by molecular beam epitaxy to form epitaxial material in the
device and reachthrough areas and amorphous silicon over the silicon dioxide.
During this step the subcollector and reachthrough join by diffusion each half-way
under the reachthrough to the device spacing separator of silicon dioxide and
amorphous silicon, the dimension of which was established in the first step. This
step is illustrated in Fig. 3.
After selective removal of the amorphous silicon, appropriate base and
emitter regions with contacts are then formed. This step is illustrated in Fig. 4.
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