Double-side corrugated cylindrical capacitor structure of high density DRAMs
US5843822A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 5, 1997 |
| Grant date | Dec 1, 1998 |
| Priority date | — |
| Expiry date | Feb 5, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D1/716
Abstract
A method of fabricating double-side corrugated cylindrical capacitor of high density Dynamic Random Access Memory (DRAM) cells. The corrugated capacitor shape is achieved by depositing the thermal chemical vapor deposition (CVD) oxide and the plasma-enhanced CVD (PECVD) oxide alternating layers. Then, the thermal CVD oxide and the PECVD oxide layers are vertically etched to form two trenches followed by laterally etched by hydrofluoric acid (HF). Because hydrofluoric acid (HF) etches the thermal CVD oxide at a slower rate than etches the PECVD oxide, a cavity is formed in each PECVD oxide layer along the trenches. Finally, polysilicon layer is deposited filling into the trenches. Therefore, the double-side corrugated shape capacitor surface is created that increases the surface area of the capacitor considerably. The cylindrical capacitor storage node of the DRAM capacitor of this method has much greater surface area so as to increase the capacitance value of the DRAM capacitor, that can achieve high packing density of the integrated circuit devices.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.