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:
Nov. 06, 2001
Filed:
Jun. 15, 2000
David L. Kencke, Portland, OR (US);
Sanjay K. Banerjee, Austin, TX (US);
Board of Regents, The University of Texas System, Austin, TX (US);
Abstract
A field effect transistor such as a flash EEPROM device has channel region between a source region and a drain region with the channel region including a silicon germanium alloy layer epitaxially grown on a silicon substrate and a silicon cap layer epitaxially grown on the alloy layer. A floating gate is provided over and insulated from the channel region, and a control gate is provided over and insulated from the floating gate. The silicon germanium alloy layer and cap silicon layer provide for enhanced secondary impact ionization when injecting electrons from the channel region into the floating gate in programming the device. In a preferred embodiment the SiGe alloy layer is graded with the germanium mole fraction increasing from zero to some maximum value in the growth direction and with the germanium layer thickness being below a critical thickness for maintaining pseudomorphic strain.