The high thermal conductivity and low thermal expansion coefficient of diamond make it an ideal choice for diode laser mounting and heat sinking applications. In this paper, we describe the fabrication of a chemical vapour deposition (CVD) diamond heat sink with integral optical fibre alignment V-grooves. Structured diamond films were produced by depositing diamond on to pre-patterned, sacrificial silicon substrates. Etch masks with windows aligned parallel to the <110> directions in the silicon substrate were used to produce V-shaped ridges and grooves by anisotropic wet etching. The etch rate of the silicon was 0.5 µm min-1 in the <100> direction. In the <111> direction, the etch rate was 2 orders of magnitude lower, giving good selectivity between the two directions. Diamond was deposited over the micromachined structures by microwave plasma chemical vapour deposition. A bias enhanced nucleation step was used to nucleate the diamond film. The thickness of the diamond film was uniform over the micromachined silicon ridges and grooves. Localised epitaxially orientated growth was observed on the top of the V-shaped ridges. The thermal properties of the CVD diamond films were modelled using a finite element technique. The model included the anisotropic thermal conductivity of the CVD diamond and indicates an optimum thickness for the diamond film of ~ 100 µm. © 1998 Elsevier Science S.A.
|Number of pages||7|
|Journal||Diamond and Related Materials|
|Publication status||Published - 1998|
- Diamond films
- Silicon substrate
- Thermal management