  Interconnect materials with ultralow dielectric constant, and good thermal
and mechanical properties are crucial for the further miniaturization of
electronic devices. Recently, it has been demonstrated that ultrathin amorphous
boron nitride (aBN) films have a very low dielectric constant, high density
(above 2.1 g/cm3), high thermal stability, and mechanical properties. The
excellent properties of aBN derive from the nature and degree of disorder,
which can be controlled at fabrication, allowing tuning of the physical
properties for desired applications. Here, we report an improvement in the
stability and mechanical properties of amorphous boron nitride upon hydrogen
doping. With the introduction of a Gaussian approximation potential (GAP) for
atomistic simulations, we investigate the changing morphology of amorphous
boron nitride with varying H doping concentrations. We found that for 8 at% of
H doping, the concentration of $sp^3$-hybridized atoms reaches a maximum which
leads to an improvement of thermal stability and mechanical properties by 20%.
These results will be a guideline for experimentalists and process engineers to
tune the growth conditions of amorphous boron nitride films for numerous
applications.
