Investigation of residual stress in structured diamond films grown on silicon

• The mechanical stress in thin diamond strips on Si was measured and simulated.
• The compressive stress from − 0.7 to − 0.1 GPa was evaluated by Raman spectroscopy.
• The stress was dependent on the manufacturing technology (top-down, bottom-up).
• The simulations described well the stress distribution across the strip.
• The simulations explained the higher thermal stress at lower deposition temperature.

Thin diamond strips on Si with the thickness of approx. 0.5 and 1 μm and two different widths (100 and 200 μm) were fabricated in two different ways: i) selective ion etching of the continuous diamond films and ii) selective area diamond growth. The stress induced in the films was measured by Raman spectroscopy. The measured values were in the range from − 0.7 to − 0.1 GPa. It was found that the stress was compressive and independent of the film thickness. In the films deposited at 950 K, more compressive stress than at 1100 K was measured. The thermal part of the stress as a consequence of heterostructure cooling from high deposition temperature down to room temperature was calculated by Finite Element Method (FEM) simulations and compared with the measurement. It was found that the calculated thermal stress of the continuous film was rather close to the stress values measured for the etched films. The qualitative distribution of the stress measured from the diamond strip center to its edge coincided very well with the FEM simulations. It was shown that relevant stress studies can be made with a relatively low spatial resolution of the Raman measurement in combination with qualitative results of FEM simulations.