Browse Prior Art Database

Diamond Optical Component Fabrication

IP.com Disclosure Number: IPCOM000104073D
Original Publication Date: 1993-Mar-01
Included in the Prior Art Database: 2005-Mar-18
Document File: 2 page(s) / 67K

Publishing Venue

IBM

Related People

Cuomo, JJ: AUTHOR [+3]

Abstract

Disclosed is a process for depositing smooth fine grain, thick samples of diamond for use in optical components. The new process recognizes the commonality between deposition and polishing and instead of the two steps, it combines the deposition and polishing into one step. Not only is the process more economical in terms of capital, space, gas handling and time, but there are unanticipated benefits.

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Diamond Optical Component Fabrication

      Disclosed  is  a  process  for depositing smooth fine grain,
thick samples of diamond for use in optical components.  The new
process recognizes the  commonality  between  deposition and
polishing and instead of the two steps, it combines the deposition
and polishing into one step.   Not  only  is  the process  more
economical  in  terms  of capital, space, gas handling and time, but
there are unanticipated benefits.

      CVD  diamond  can  be  deposited  at  high  rates,  for
example,  greater  than  400&mu./hr.   With such high rates,
structural  and  optical  components   are   fast   becoming
possible.    A  problem with high rate diamond films is that the
topography of the deposit is rough, mottled and in  some cases
strongly faceted.  Correspondingly, the grains of the films are large
and irregular which, along  with  the  rough surface  scatter light.
Such surfaces are inconsistent with most  optical  applications  and
substrates   for   thermal management applications.

      Standard diamond polishing using metal polishing wheels can  be
used  to achieve the optical finishes necessary for devices, but the
polishing times are prohibitive.  Recently, high  temperature
~  800ºC  polishing  using metal  laps in the presence
of either hydrogen or oxygen has decreased polishing times from tens
of  hours  to  tens  of minutes.  The high temperature and the
reactive gas enhances the  chem-mechanical  polishing of diamond.
It is believed [1, 2]  the polishing process is a  multiple  step
process  comprising  of  a graphitizing the diamond surface, followed
by the formation of a carbide  in  the  metal  lay.  The  reactive
gas then forms a volatile compound, CH sub 4 if H sub 2 is used and
CO sub 2 is  O sub  2 is used.  The metal lap is a carbide former;
Fe, Ni, cast iron, and Mo have been used.

      The  deposition  environm...