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Scanning Laser Cleaning of Silicon Wafer for Low Temperature Epitaxy in Ultra-High Vacuum

IP.com Disclosure Number: IPCOM000111999D
Original Publication Date: 1994-Apr-01
Included in the Prior Art Database: 2005-Mar-26
Document File: 2 page(s) / 52K

Publishing Venue

IBM

Related People

Chu, JO: AUTHOR [+5]

Abstract

Disclosed is a method for cleaning uniform or patterned silicon wafers before further epitaxial growth. Low Temperature Epitaxial growth (LTE) under Ultra-High Vacuum (UHV) has been pursued successfully in recent years. A simple cleaning method based on dipping the wafer in the hydrofluoric acid (HF) without rinsing with DI water is known to provide a clean silicon wafer for the LTD/UHV silicon growth at relatively low temperatures of about 650ºC. After the removal of surface oxides by the dilute HF, the silicon surface is passivated by absorbed or chemisorbed hydrogen. The passivated surface is observed to be stable in air for several tens of minutes.

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Scanning Laser Cleaning of Silicon Wafer for Low Temperature Epitaxy
in Ultra-High Vacuum

      Disclosed is a method for cleaning uniform or patterned silicon
wafers before further epitaxial growth.  Low Temperature Epitaxial
growth (LTE) under Ultra-High Vacuum (UHV) has been pursued
successfully in recent years.  A simple cleaning method based on
dipping the wafer in the hydrofluoric acid (HF) without rinsing with
DI water is known to provide a clean silicon wafer for the LTD/UHV
silicon growth at relatively low temperatures of about 650ºC.
After the removal of surface oxides by the dilute HF, the silicon
surface is passivated by absorbed or chemisorbed hydrogen.  The
passivated surface is observed to be stable in air for several tens
of minutes.

      It is conceivable that some small amount of oxygen, hydroxyl
ion, carbon, or water is absorbed or attached to the HF
dipped/cleaned silicon surface.

      The process of the present invention is to remove the oxygen,
hydroxyl ions or water without heating the whole wafer to

1000ºC or higher for 1/2 hour which is required in a
conventional prebake cleaning in hydrogen at pressure of a few Torr.

      It is also proposed to remove carbon without heating the wafer
in oxygen or ozone at 375ºC, and/or to remove the oxygen
without heating in hydrogen gas at 1000ºC for 1/2 hour.

      By scanning with a line shaped laser beam, typically, argon ion
laser or a repetitively pulsed excimer laser of suff...