Diffusion transistor  From Wikipedia, the free encyclopedia
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search  A diffusion transistor is any transistor formed by
diffusing dopants into a semiconductor substrate. Diffusion
transistors include some types of both bipolar junction
transistors and field-effect transistors. The diffusion process
was developed later than the alloy junction and grown junction
processes.  Bell Labs developed the first prototype diffusion
transistors in 1954.[1]  Diffused-base transistor[edit]  The
earliest diffusion transistors were diffused-base transistors.
These transistors still had alloy emitters and sometimes alloy
collectors like the earlier alloy-junction transistors. Only the
base was diffused into the substrate. Sometimes the substrate
formed the collector, but in transistors like Philco's micro-
alloy diffused transistors the substrate was the bulk of the
base.  Double diffusion[edit]  At Bell Labs Calvin Souther
Fuller produced basic physical understanding o