Effect of oxygen on growth and properties of diamond thin film deposited at low surface temperature

Abstract

Polycrystalline diamond thin films are grown on a p-type Si (100) single crystal substrate at a low surface deposition temperature of 455°C using a microwave plasma enhanced chemical vapor deposition process in an Ar-rich Ar∕H2∕CH4 plasma containing different oxygen levels from 0% to 0.75%. The surface deposition temperatures are measured and monitored by an IR thermometer capable of working in a plasma environment without any interference from the plasma emissions. The lower surface deposition temperature at high microwave power of 1300W and higher gas pressure of 95torr is achieved by active cooling of the substrate from the backside using a specially designed cooling stage. An enhanced growth rate from 0.19to0.63μm∕h is observed with varying oxygen from 0% to 0.75% in the plasma. Diamond grain size also increased from 0.69μm for the sample with no oxygen to 1.74μm for the sample with 0.75% oxygen. The diamond films are characterized using x-ray diffraction, environmental scanning electron microscopy field emission gun, Raman spectroscopy, and x-ray photoelectron spectroscopy. The enhanced growth rate is correlated with the enhanced atomic hydrogen to C2 ratio with increasing oxygen concentration in the plasma, which is measured by an in situ optical emission spectroscopy.

Investigation on crystalline structure, boron distribution, and residual stresses in freestanding boron-doped CVD diamond films

“…This is also supported by recent observations in Ref. 19 i.e., the growth orientation varied from /1 1 1S to /1 1 0S by adding oxygen in reaction gases of CH 4 and H 2 . However, at a high B-flow rate (20 sccm), the [1 1 1] texture is re-dominated in the corresponding product.…”

Nanocrystalline diamond film growth on plastic substrates at temperatures below100 °Cfrom low-temperature plasma

“…Hence we introduced CO 2 into the reaction gas mixture to enhance the etching effect at low substrate temperatures by oxygen. [17][18][19] We applied a water cooled substrate holder to maintain the substrate below 100°C. The substrate temperature was monitored by a K-type thermocouple in contact with the substrate surface.…”

Homo-epitaxial growth of single crystal diamond in the purified environment by active O atoms

“…It can be observed that intensities of C 2 , CH, Hα radicals decrease in Fig.7. Meanwhile, the band at 400-405nm gradually disappears with O 2 addition and emissions at 390nm become stronger, indicating the amount increase of CO present in the plasma [25]. The decrease rate of C 2 radicals is much larger than that of CH and radicals.…”

“…In Fig.9, dependence of and on O 2 concentration is shown and it is found that rises firstly and then falls with increasing O 2 concentration. It is because that O 2 will react with CH radicals preferentially under low concentration of O 2 [25]. With increasing O 2 concentration, the consumption of CH radicals reaches saturation.…”