摘要:
A process for forming an integrated circuit calls for the provision of at least one matrix of non-volatile memory cells (1) including an intermediate dielectric multilayer comprising a lower silicon oxide layer (7), an intermediate silicon nitride layer (8) and an upper silicon oxide layer (10) and the simultaneous provision in zones peripheral to the memory cells of at least one first (2) and one second (3) transistor type having gate dielectric of a first and a second thickness respectively. After formation of the floating gate of the cells with a gate oxide layer (5) and a polycrystalline silicon layer (6) and the formation of the lower silicon oxide layer (7) and of the intermediate silicon nitride layer (8), the process in accordance with the present invention includes:
removal of said layers from the zones peripheral (R2,R3) to the matrix; formation of a first silicon oxide layer (9) over the substrate in the areas (R2,R3) of both types of transistor (2,3); removal of the preceding layer (9) from areas (R3) assigned only to the transistors (3) of the second type; deposition of said upper silicon oxide layer (10) over the memory cells (1), over the first silicon oxide layer (9) in the areas (R2) of the transistors (2) of the first type and over the substrate (4) in the areas (R3) of the transistors of the second type; and formation of a second silicon oxide layer (11) in the areas (R2,R3) of both types of peripheral transistors (2,3).
摘要:
A method comprising the steps of depositing a first (12) and second (17) polysilicon layer, separated by an oxide layer (13); selectively etching the second polysilicon layer (17) to form first gate regions (18); forming first substrate regions (26, 29) in the substrate (2) and laterally in relation to the first gate regions; selectively etching the first polysilicon layer (12) to form second gate regions of a length greater than the first gate regions (18); and forming in the substrate, laterally in relation to the second gate regions (12) and partially overlapping the first substrate regions (26, 29), second substrate regions (37, 38) of a higher doping level than the first substrate regions (26, 29).
摘要:
A process of fabricating a floating-gate memory device, the process including the steps of: forming a stack of superimposed layers including a floating gate region (20), a dielectric region (21), and a control gate region (22); and forming an insulating layer (35) of oxynitride to the side of the floating gate region to completely seal the floating gate region outwards and improve the retention characteristics of the memory device. The insulating layer (35) is formed during reoxidation of the sides of the floating gate region (20), after self-align etching the stack of layers (20-22) and implanting the source/drain of the cell.
摘要:
A method comprising the steps of depositing a first (12) and second (17) polysilicon layer, separated by an oxide layer (13); selectively etching the second polysilicon layer (17) to form first gate regions (18); forming first substrate regions (26, 29) in the substrate (2) and laterally in relation to the first gate regions; selectively etching the first polysilicon layer (12) to form second gate regions of a length greater than the first gate regions (18); and forming, in the substrate, laterally in relation to the second gate regions (12) and partially overlapping the first substrate regions (26, 29), second substrate regions (37, 38) of a higher doping level than the first substrate regions (26, 29).
摘要:
The method described provides for the formation of thin thermal oxide on areas of a silicon die intended for memory cells and other components of the peripheral circuits of the memory. To improve the quality of the oxide of the cells essentially in terms of resistance to degradation due to the passage of charges through it during the operation of the memory, the method provides for a step for the high-temperature nitriding of the oxide. According to a variant, the nitrided oxide formed on the areas intended for the components of the peripheral circuits is removed and then formed again by a similar thermal oxidation treatment followed by high-temperature nitriding.
摘要:
A process for forming an integrated circuit calls for the provision of at least one matrix of non-volatile memory cells (1) having an intermediate dielectric multilayer including at least a lower dielectric material layer (8) and an upper silicon oxide layer (9) and the simultaneous provision in zones peripheral to the matrix of at least one first transistor type (2) having gate dielectric of a first thickness. After formation of the floating gate with a gate oxide layer (4) and a polycrystalline silicon layer (5) and the formation of the lower dielectric material layer (8), the process in accordance with the present invention calls for:
removal of said layers from the peripheral zones (R2) of the matrix; deposition of said upper silicon oxide layer (9) over the memory cells (1),and over the substrate (3) in the areas (R2) of the peripheral transistors (2); and formation of a first silicon oxide layer (10) at least in the areas (R2) of the peripheral transistors (2).
To provide additionally a second transistor type having gate dielectric of a second thickness, indicatively thinner than said first thickness, successive steps are added in accordance with the present invention.
摘要:
The use of an O-N-RTN (Oxide-Nitride-Rapid Thermal Nitrided Polysilicon) interpoly dielectric multilayer instead of a customary O-N-O (Oxide-Nitride-Oxide) multilayer in the floating gate structure of a progammable, read-only memory cell has beneficial effects on the performance of the cell and facilitates its scaling down.