Method for making a buried contact
US5550085A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 7, 1995 |
| Grant date | Aug 27, 1996 |
| Priority date | — |
| Expiry date | Sep 7, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/76895
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method of forming damage-free buried contacts in a semiconductor substrate without the trenches and pitted areas can be carried out by forming a silicon oxide layer as a gate dielectric layer on top of the substrate, forming a first polysilicon layer on top of the silicon oxide layer, anisotropically etching away the first polysilicon layer by using a first mask and a first etching gas that has high etching selectivity between polysilicon and silicon oxide such that a first portion of the polysilicon layer is left on the top surface of the substrate except the area defining a buried contact, forming in the substrate a zone of a second conductivity type at the area defining the buried contact by implanting impurity ions, removing the silicon oxide layer over the area defining the buried contact and removing the masking layer over the first portion of the polysilicon layer, depositing sequentially a conducting layer and a second polysilicon layer, anisotropically etching the second polysilicon layer over an area defining a transistor gate electrode and interconnect by using a second mask and a second etching gas that has high etching selectivity between polysilicon and the conducti…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.