Method for forming gate dielectric layer in NROM
AssigneeMacronix International Co., Ltd.
InventorKent Kuohua Chang
Life of this patent
Estimating the term…
Abstract
In fabricating nitride read only memory, a zirconium oxide layer has high dielectric constant and a zirconium oxide layer is replaced conventional tunnel oxide layer. Zirconium oxide layer can increase coupling ratio of gate dielectric layer and reliability for nitride read only memory type flash memory is improved. This invention, a substrate is provided and a zirconium oxide layer is formed on substrate by reactive magnetron sputtering and a silicon nitride layer is sandwiched between a zirconium oxide layer and a silicon oxide layer. Then, an ONO layer (oxide-nitride-oxide layer) is formed. The method is using zirconium oxide as gate dielectric can reduce leakage current, increase drain current, improve subthreshold characteristics, and electron and hole mobilities.
Claims7
A method for forming nitride read only memory, said a method comprising:
- providing a substrate;
- forming a zirconium oxide layer on said substrate by using sputtering method;
- performing annealing treatment to said zirconium oxide layer;
- forming a silicon nitride layer on said zirconium oxide layer;
- forming a silicon oxide layer on said silicon nitride layer;
- forming a polysilicon layer on said silicon oxide layer;
- forming a photoresist over said polysilicon layer and defining a gate pattern on said photoresist;
- etching said polysilicon layer, said silicon oxide layer, said silicon nitride layer, and said zirconium oxide layer to form gate electrode by using said photoresist as a mask;
- removing said photoresist;
- forming a spacer on sidewall of said gate electrode;
- and
- forming a source and a drain in said substrate.
Dependencies are inferred from the claim text.