Low Pressure Diamond Growth Using a Secondary Radical Source

Abstract

Pu O'C reoDrt'i turoen for this collection of information is estimated to average 1 hour Per response. including the time for reviewing instructions. searching existing data sources. gatheri o antid -intaining the data needed, and completing and revie.ng the :ollec-ton of information Send comments regarding this burden estimate Or any other aspect of this Collecti of information, includong suggestions for reducing this ouraren to Washington Headduarters Services. )iDectorate for information Operations and Repofts, Approved for public release; distribution is unlimited. ABSTRACT (Maximum 200 words)A novel method for chemical vapor deposition and atomic layer epitaxy using radical precursors under medium vacuum conditions is being developed. Fluorine atoms are generated by thermal dissociation in a hot tube and abstract hydrogen atoms from precursor molecules injected immediately downstream of the source, generating radicals with complete chemical specificity.The radical precursors are then transported to the growing substrate surface under nearly collision-free conditions. To date we have grown diamond films from CC13 or CH 3 radicals together with atomic hydrogen, generated by injecting CHCI3 or C-4 and H2 into the F atom stream at reactor pressures between 10-4 and 10-2 Tort. This approach should be ideal for lowtemperature growth and atomic layer epitaxy: growth rates remain relatively high because activation energies for radical reactions are typically small and because the cycle times for atomic layer epitaxy can be reduced to the msec range by fast gas-stream switching, and cont tion and segregation are minimized by keeping the surface "capped' by chemisobe intermediates. ABSTRACT A novel method for chemical vapor deposition and atomic layer epitaxy using radical precursors under medium vacuum conditions is being developed. Fluorine atoms are generated by thermal dissociation in a hot tube and abstract hydrogen atoms from precursor molecules iajected immediately downstream of the source, generating radicals with complete chemical specificity. The radical precursors are then transported to the growing substrate surface under nearly collisionfree conditions. To date we have grown diamond films from CC1 3 or CH3 radicals together with atomic hydrogen, generated by injecting CHC1 3 or CM 4 and H2 into the F atom stream at reactor pressures between 10 -4 and 10-2 Torr. This approach should be ideal for low-temperature growth and atomic layer epitaxy: growth rates remain relatively high because activation energies for radical reactions are typically small and because the cycle times for atomic layer epitaxy can be reduced to the msec range by fast gas-stream switching, and contamination and segregation are minimized by keeping the surface "capped" by chemisorbed intermediates.

High—temperature Sensors Based on SiC and Diamond Technology

“…Various growth mixtures have been explored, aiming to increase deposition rates or reduce growth temperatures without compromising growth rate and film quality. Four main areas of approach have been widely researched: (1) oxygen additions [41]; (2) CO-and CO 2 -based mixtures [42,43]; (3) additions of halogens such as fluorine and chlorine [44]; and (4) additions of noble gases such as neon and argon [45]. A significant step forward in rationalizing the experimental data for crystalline diamond growth chemistries was proposed by Bachmann et al [46].…”

Progress Toward Atomic Layer Epitaxy of Diamond Using Radical Chemistry

“…We employed flow rates of 1-10 sccm of F 2 , 5-60 sccm of H 2 , and 5-60 sccm of 3 CH 4 or C 2 H 2 . Previous experiments utilized CHC1 3 as a precursor (2,4) and experiments with CHF 3 are underway. The chamber pressure rose to 10-3 -10-1 Torr during growth.…”

“…The chamber pressure rose to 10-3 -10-1 Torr during growth. We previously obtained evidence for diamond growth on diamond (1(X)) substrates using CHCI 3 or CH4 as precursors (2,4), including thickness increases and surface morphological features suggestive of growth. However, we sought more definitive evidence for diamond growth, and in the present work we have used polycrystalline copper and nickel wires seeded with 5-8 ptm natural diamond grit as substrates, held at temperatures between 500 and 600 *C.…”