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:
Jul. 08, 2003
Filed:
Jul. 20, 2000
Stepan Essaian, San Jose, CA (US);
Abdalla A. Naem, Overijse, BE;
National Semiconductor Corporation, Santa Clara, US;
Abstract
A silicon-germanium alloy of high crystal quality and containing uniform concentrations of dopant and germanium is formed by applying laser energy to a doped amorphous/polysilicon germanium layer overlying epitaxial silicon. Energy transferred from the laser beam causes melting of the germanium and the underlying silicon, resulting in diffusion of germanium and dopant into the melted silicon. Subsequent cooling and crystallization of the silicon/germanium/dopant melt produces a high quality crystal lattice uniformly incorporating germanium and dopant within its structure. Efficient energy transfer from the laser beam to the underlying germanium and silicon may be promoted by patterning an anti-reflective coating over the amorphous/polysilicon doped germanium prior to exposure to laser radiation. The process is particularly suited for forming the silicon-germanium base of a heterojunction bipolar transistor device.