Methods to improve electrical performance of ZrO2 based high-K dielectric materials for DRAM applications

摘要

A method for reducing the leakage current in DRAM MIM capacitors comprises forming a multi-layer dielectric stack from an amorphous highly doped material, an amorphous high band gap material, and a lightly-doped or non-doped material. The highly doped material will remain amorphous (<30% crystalline) after an anneal step. The high band gap material will remain amorphous (<30% crystalline) after an anneal step. The lightly-doped or non-doped material will become crystalline (≧30% crystalline) after an anneal step. The high band gap material is formed between the amorphous highly doped material and the lightly or non-doped material and provides an intermediate barrier to conduction through the multi-layer dielectric stack.

主权项

1. A method for forming a capacitor stack comprising:
forming a flash layer above a first electrode layer; forming a first dielectric layer above the flash layer, wherein the first dielectric layer comprises metal oxide, wherein the first dielectric layer comprises a dopant, and wherein the dopant comprises silicon; inserting a high band gap fourth dielectric layer within the first dielectric layer during the forming of the first dielectric layer; forming a high band gap second dielectric layer above the first dielectric layer; forming a third dielectric layer above the high band gap second dielectric layer, wherein the third dielectric layer comprises metal oxide, wherein the third dielectric layer comprises a second dopant, and wherein the second dopant comprises silicon; and forming a capping layer above the third dielectric layer, wherein the flash layer and the capping layer each comprise titanium oxide.