The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 12, 2004
Filed:
Dec. 21, 2001
Applicant:
Inventors:
Mariam G. Sadaka, Phoenix, AZ (US);
Jonathan K. Abrokwah, Scottsdale, AZ (US);
Assignee:
Freescale Semiconductor, Inc., Schaumburg, IL (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01L 2/100 ;
U.S. Cl.
CPC ...
H01L 2/100 ;
Abstract
A method is provided for etching quaternary interface layers of In Ga As P which are formed between layers of GaAs and InGaP in heterojunction bipolar transistors (HBTs). In accordance with the method, the interface is exposed by etching the GaAs layer with an etchant that is selective to InGaP. The interface is then etched with a dilute aqueous solution of HCl and H O that is selective to InGaP. The controlled etching provided by this methodology allows HBTs to be manufactured with more sophisticated, near ideal designs which may contain multiple GaAs/InGaP interfaces.