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.
A process is described for fabricating a self-aligned emitter having a shallow junction and low leakage, and suitable for use in high frequency transistors.
English (United States)
This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately
53% of the total text.
Page 1 of 2
Polysilicon Source And Contact
A process is described for fabricating a self-aligned emitter having a shallow
junction and low leakage, and suitable for use in high frequency transistors.
The process is described in Figs. 1A-1E. In Fig. 1A, a base region 10 is
formed in an epi layer 12 united to a substrate 14 by the following steps:
Recessed oxide regions 16 and 18 are formed in the epi layer 12, leaving
openings 20 therebetween. A layer of silicon dioxide 22 is also formed across
the surface of the layer 12 to a thickness of approximately 1600 angstroms.
Photoresist 24 is applied across the surface of layer 22 and openings are made
in the layer over the active regions 20. An ion implant of B/11/ is directed into the
region 10 as a base region. The photoresist 24 is removed and a layer of silicon
nitride 26/silicon dioxide 28 and silicon nitride 30 are, formed across the layer 22
to thicknesses of 500 angstroms, 5000 angstroms and 500 angstroms, as shown
in Fig. 1B.
A dove-shaped opening 32 is made in the layers 26, 28 and 30 by a suitably
controlled reactive ion etch (RIE) process, after appropriate development of a
photoresist layer (not shown) on the layer 30. The layer 22 is suitably etched to
expose the surface of layer 10, and an emitter ion implant is made through the
opening 32. A polysilicon layer 34 is formed across the layer 30 and in the
opening 32, as shown in Fig. 1C.
The polysilicon is formed to a thickness of approximately 4000 angstroms.
The polysilicon 34 in the opening 32...