Browse Prior Art Database

Controlled Surface Texturing of Materials

IP.com Disclosure Number: IPCOM000122000D
Original Publication Date: 1991-Oct-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 2 page(s) / 82K

Publishing Venue

IBM

Related People

Oehrlein, GS: AUTHOR [+3]

Abstract

Disclosed is a method for controlled surface texturing of materials by non-uniform masking of the material using plasma-formed particles with a uniform size followed by directional etching of the material.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Controlled Surface Texturing of Materials

      Disclosed is a method for controlled surface texturing of
materials by non-uniform masking of the material using plasma-formed
particles with a uniform size followed by directional etching of the
material.

      Texturing of the surfaces of materials is useful for
applications requiring large surface areas, e.g., anti-reflection
coatings in solar- cells, catalyst applications, or high-density
storage capacitors.  In the last application, a capacitor structure
with corrugated surfaces, e.g., a large number of mini-trenches
instead of a single trench, is employed and has improved capacitance
density.  Surface texturing is typically produced by micromasking and
directional etching, e.g., sputter deposition of involatile material,
incomplete removal of the native oxide, etc., followed by directional
etching [1]. Unfortunately, the shape of the micromasks is not
controlled in this approach and the performance of the surface
texture cannot easily be optimized for the particular application.

      Controlled surface texturing of materials can be achieved using
the following approach:  in recent work it has been shown that RF
discharges are prone to particular formation via negative ions
localized at the sheath boundary just above the wafer surface [2].
These particles remain in the negative charge state for a long time
and grow in size, e.g., up to mm size, while floating above the
wafer.  When the discharge is extinguished, neutralized particles
deposit onto the wafer surface.  The particle deposition step is then
followed by reactive ion etching to produce micromasking.  It has
been shown that the size distribution of the particles is highly
uniform [2].  The particle size can be chosen by selecting the time
when the plasma is extinguished.

      In a fabrication sequence, this approach would be conducted in
the following fashion:  initially a particle forming discharge is
employed, e.g., an Ar discharge, which does not lead to any
significant...