Browse Prior Art Database

Low High Polysilicon Process for Smooth Films

IP.com Disclosure Number: IPCOM000048958D
Original Publication Date: 1982-Apr-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Gardiner, JR: AUTHOR [+3]

Abstract

This process provides smooth polysilicon film with improved breakdown characteristics of oxides grown on polysilicon.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 1

Low High Polysilicon Process for Smooth Films

This process provides smooth polysilicon film with improved breakdown characteristics of oxides grown on polysilicon.

There has been a significant problem on breakdown between polysilcon layers. The integrity or breakdown characteristics of oxides grown on polysilicon is significantly less than that of other thermally grown silicon dioxide. This difference has been attributed to asperities on the polysilicon or in other words, the surface roughness of the polysilicon. The asperities or surface roughness can be seen by Talysurf measurements. If severe enough, the roughness will result in hazy or cloudy films, especially with thicker films.

Extremely smooth and very shiny polysilicon films can be obtained by depositing an initially very thin, smooth film (probably amorphous), at a low initial deposition temperature at 550 degrees C for 15 minutes in an LPCVD (low pressure chemical vapor deposition) reactor, followed by a 15 minute warm-up period to 625 degrees C. After the warm-up, the remainder of the film is deposited at 625 degrees C.

Talysurf traces were taken on films of about 1 MU m in thickness deposited on SiO(2)-covered silicon, bare silicon, and sapphire wafers. Talysurf traces showed the smoothness to be generally better than 50 angstroms. The films were very shiny and possessed properties which can achieve better breakdown characteristics.

1