CVD diamond growth in a microwave plasma with elevated SiH4 content: from SiV centers to SiC and Si phases formation

Conclusions:

• A wide spectra of SiH4/CH4/H2 gas mixtures was used to grow diamond, SiC and Si materials;
• Low Si contents (less than 0.7% Si/C) leads to formation of SiV centers. Integration coefficent was found to be (1.1±0.5)·10^-3;
• Higher Si contents leads to formation of nano- and microcrystalline 3C-SiC.
• Composite Diamond-SiC materials were synthesized.

CVD diamond growth in a microwave plasma with elevated SiH4 content: from SiV centers to SiC and Si phases formation

(1) General Physics Institute RAS, Moscow 119991, Russia;

(2) National Research Nuclear University MEPhI, Moscow 115409, Russia;

(3) Harbin Institute of Technology, 92 Xidazhi Str., Harbin 150001, P.R. China;

(4) Institute of Radio Engineering and Electronics RAS, Moscow 125009, Russia;

(5) Belarusian State University, Minsk 220030, Republic of Belarus.

Low concentrations of SiH4

0% - 1%

Single-crystalline

Polycrystalline

Moderate concentrations 0.1 - 0.5 SiH4/CH4

• Microcrystalline
• (grain size 500 nm)

Nanocrystalline

(grain size 70 nm)

Above 0.5 SiH4/CH4

Pure SiH4 (no CH4)

Integrated SiV PL intensity (triangles) and concentration of silicon [Si] (circles) in Si-doped SC diamond films

PL spectra for Si-doped epitaxial diamond films

(the percentage [SiH4/CH4] varied from zero to 0.7%)

Raman and PL studies of Microcrtalline films

Raman and PL studies of Nanocrtalline films

SEM images of "1000 nm"-thick nanocrystalline (a) and microcrystalline diamond films

SiV distribution in an epitaxial film

Raman spectra of

CVD-grown SiC film

Silicon Carbide film on Si (100), grown in

H2-CH4-SiH4 gas mixture

Si concentration in pits (SIMS)

PL SiV integrated intensity in pits along the diagonal over the sample

The map of pits etched in the course of SIMS measurements

Synthesis of DIamond/SiC composite

Co-Deposition of SiC and Diamond

Integration coefficient:

f = [Si/C]dia/[Si/C]gas = (1.1±0.5)·10^-3

SEM of Si crystals on diamond

Diamond crystals in SiC enviroment

Cross-section of SiC/Diamond composite

on Si (100) substrate

Raman spectra of Si crystals on diamond

Nanocrystalline 3C-SiC (nc-SiC)

Pure CH4 (no SiH4)

Layered SiC-Diamond structures

Substrates used for 3C-SiC deposition:

XRD spectra of NC-SiC

Highly (100)-oriented

Crysllite size of 35 nm

Surface of nc-SiC on diamond after Si substrate removal

• Si (100) and (111)
• AlN (polycrystallne)
• Ge (100)
• GaN (100)
• Single-crystalline diamond

SiC-Diamond layered structure

(cross-section)

Diamond seed in SiC enviroment

(initial seed size 50 nm)

Zone of interest:

0 - 0.5 of SiH4/CH4

PL spectra of Si-free epitaxial diamond

High-quality low-impurities CVD diamonds

Condition: no Si present in CVD reactor or on the chamber walls

Silicon in diamond

Silicon Carbide formation

Single Color Centers

Polycrystalline SiC film*

*Zhuang, Hao, and Xin Jiang. "Growth controlling of diamond and β-SiC microcrystals in the diamond/β-SiC composite films." Surface and Coatings Technology 249 (2014): 84-89.

MPCVD growth (ARDIS-100*)

Characterization of the samples

*Commercially available at

http://www.cvd-diamond.ru/eng/

Diamond syntesis:

• MW power: 2.0-3.5 kW
• Pressures: 60-80 Torr
• Gas flow: 100 - 500 sccm
• CH4-H2 ratio: 0.5% - 10%
• Temperature: 600 - 850 °C
• Time 10 minutes: - 50 hours

• Raman spectroscopy
• Scanning Electron Microscopy
• Photoluminescence measurements
• X-ray Diffraction
• Secondary ion mass spectrometry
• etc.

Thickness - 1-200 μm

Thank you for attention!