Patent ID: 6359305
Filing Date: 2002-03-19
Classification: G11C,H01L

Abstract:
An EEPROM floating gate memory device comprising:a) a substrate of semiconductor material having a channel region of a first type of conductivity between a first and a second region of a second type of conductivity, said channel region being formed at a surface of said semiconductor substrate, said channel region being capable of passing an electric current between said first and said second region; b) a first level of patterned conducting material constituting a floating gate and extending over said channel region substantially between said first and said second region, said first level of conducting material being electrically insulated from said semiconductor substrate by a first layer of dielectric material; c) a second level of patterned conducting material constituting a control gate overlying said floating gate, said second level of conducting material being electrically insulated from said first level of conducting material by second layer of dielectric material; d) a field oxide area formed in an isolation trench abutting said channel region, wherein said field oxide area flanks said floating gate; e) a tunnel area defined along a surface of one of said first and second regions, said tunnel area being bordered on one side by a base of a portion of a side wall of said floating gate and being covered with a third layer of dielectric material thinner than said first layer of dielectric material; and f) an appendix of conducting material juxtaposed along said portion of said side wall of said floating gate, a base of said appendix abutting a surface of said third layer of dielectric material covering said tunnel area, said appendix being electrically connected to said patterned first level of conducting material constituting said floating gate along a periphery of said floating gate in a direction intersecting said channel, said appendix being juxtaposed along said periphery of said floating gate in a direction parallel to said channel and abutting said field oxide, said appendix forming a self-aligned end cap for said floating gate.