The following operators can be used to better focus your queries.
( ) , AND, OR, NOT, W/#
? single char wildcard, not at start
* multi char wildcard, not at start
(Cat? OR feline) AND NOT dog?
Cat? W/5 behavior
(Cat? OR feline) AND traits
Cat AND charact*
This guide provides a more detailed description of the syntax that is supported along with examples.
This search box also supports the look-up of an IP.com Digital Signature (also referred to as Fingerprint); enter the 72-, 48-, or 32-character code to retrieve details of the associated file or submission.
Concept Search - What can I type?
For a concept search, you can enter phrases, sentences, or full paragraphs in English. For example, copy and paste the abstract of a patent application or paragraphs from an article.
Concept search eliminates the need for complex Boolean syntax to inform retrieval. Our Semantic Gist engine uses advanced cognitive semantic analysis to extract the meaning of data. This reduces the chances of missing valuable information, that may result from traditional keyword searching.
Symmetrical bipolar-transistors can be fabricated by using selective epitaxy and relying on the faster oxidation rate of p+ polysilicon to self-align the emitter region.
English (United States)
This text was extracted from a PDF file.
100% of the total text.
Page 1 of 1
A Simple Symmetrical Transistor Using Selective Epitaxy
Symmetrical bipolar-transistors can be fabricated by using selective epitaxy
and relying on the faster oxidation rate of p+ polysilicon to self-align the emitter
The process deposits oxide, polysilicon and oxide layers on a substrate in
which trenches and a subcollector region have already been formed. The layers
which have been deposited on the surface are then etched to form emitter and
reach-through regions. Following, thereto, p+ polysilicon is deposited a reactive
ion etched to form polysilicon sidewalls in the emitter and the reach-through
etched areas. Epitaxial silicon is selectively grown in the openings such that an
epitaxial gr region and a polysilicon growth region are formed adjacent respective
single crystal and polycrystalline regions. This results in an epitaxial growth
region which has a smaller width at its top than at its bottom. The last mentioned
epitaxial region is N- conductivity type. At this point the self-aligned oxide can be
grown relying on the fewer oxidation use of the highly doped polysilicon with
respect to the exposed single crystal emitter region. After ion implanting the
base and forming an emitter by outdiffusion from an N+ poly region, base, emitter
and collector contacts are formed.