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:
Sep. 10, 1996
Filed:
Jun. 22, 1995
Hering-Der Chiou, Tempe, AZ (US);
Geoffrey J Crabtree, Chandler, AZ (US);
Motorola Inc., Schaumburg, IL (US);
Abstract
A method for fabricating semiconductor substrates with resistivity below 0.02 ohm-cm is provided. This low resistivity is achieved by doping a silicon melt with a phosphorus concentrations above 1.times.10.sup.18. The silicon melt is also doped with a germanium concentration that is 1.5 to 2.5 times that of the phosphorus concentration and a stress and dislocation free crystalline boule is grown. Phosphorus in high concentrations will induce stress in the crystal lattice due to the difference in the atomic radius of silicon atoms versus phosphorus atoms. Germanium compensates for the atomic radius mismatch and also retards the diffusion of the phosphorus as the diffusion coefficient remains relatively constant with a doping of 1.times.10.sup.18 to 1.times.10.sup.21 atoms per cm.sup.3. This will retard phosphorus from diffusing into an overlying epitaxial layer and retard other layers formed on the substrate from being auto-doped.