Method of fabricating an MOS memory array having electrically-programmable and electrically-erasable storage devices incorporated therein
DCFirst Claim
1. A method of constructing a tunnel dielectric for an MOS device such that charge carriers supplied by an active region in the device can be transported through said tunnel dielectric, said method comprising the steps of:
- forming an oxide layer over the active region to provide said tunnel dielectric; and
converting at least a portion of said oxide layer to an oxynitride material, said oxynitride material exhibiting a relatively low potential barrier to charge carriers tunnelling therethrough.
8 Assignments
Litigations
0 Petitions
Accused Products
Abstract
A method for fabricating an MOS memory array is disclosed, wherein the method includes steps for constructing electrically-programmable and electrically-erasable memory cells (2, 198, 200) in combination with assorted peripheral devices (202, 204, 206) on a semiconductor substrate (8, 71). Tunneling regions (20, 78) are formed in the substrate (8, 71) and thin tunnel dielectrics (22, 84) comprised of silicon dioxide/oxynitride material are grown over the tunneling regions (20, 78) to facilitate transport of charge carriers between the tunneling regions (20, 78) and subsequently-fashioned floating gate structures (14R, 14L, 156) in the memory cells (2, 198, 200). A first layer of doped polycrystalline silicon is then deposited over the substrate and etched to define large polysilicon areas. An oxide layer is grown over the large polysilicon areas in a manner such that out-diffusion of the impurity present in the large polysilicon areas is prevented. Thereafter, a second layer of doped polycrystalline silicon is deposited over the substrate and etched together with the large polysilicon areas to define the memory cell floating gate structures (14 R, 14L, 156) as well as various memory cell program and control gates (16R, 16L, 40R, 40L, 128, 132) and peripheral device control gates (136, 138). Source and drain regions (34, 36, 58, 60, 64, 66, 168-179) for the memory cells (2, 198, 200) and the peripheral devices (202, 204, 206) are established by implanting an impurity in the semiconductor substrate (8, 71), using the memory cell program and control gates (16R, 16L, 40R, 40L, 128, 132) and the peripheral device control gates (136, 138) for alignment. Protective coverings of refill oxide (188) and VapOx (190) are formed over the substrate to complete the fabrication process.
122 Citations
11 Claims
-
1. A method of constructing a tunnel dielectric for an MOS device such that charge carriers supplied by an active region in the device can be transported through said tunnel dielectric, said method comprising the steps of:
-
forming an oxide layer over the active region to provide said tunnel dielectric; and converting at least a portion of said oxide layer to an oxynitride material, said oxynitride material exhibiting a relatively low potential barrier to charge carriers tunnelling therethrough. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. A method of forming an interpoly oxide layer of predetermined thickness on a first semiconductor gate in an MOS device fabricated on a substrate such that said interpoly oxide layer exhibits high breakdown voltages, low surface charge states and low mobile ion contamination, said method comprising the steps of:
-
thermally growing an oxide layer over the first semiconductor gate in an atmosphere containing oxygen and gaseous hydrochloride at a temperature of approximately 800°
C. until the thickness of said oxide layer reaches approximately 100 A.; andcontinuing to grow said oxide layer in an atmosphere containing oxygen and gaseous hydrochloride at a temperature of at least approximately 1,000°
C. until said oxide layer reaches the predetermined thickness. - View Dependent Claims (11)
-
Specification