  We investigated the use of dielectric layers produced by atomic layer
deposition (ALD) as an approach to strain mitigation in composite
silicon/superconductor devices operating at cryogenic temperatures. We show
that the addition of an ALD layer acts to reduce the strain of spins closest to
silicon/superconductor interface where strain is highest. We show that
appropriately biasing our devices at the hyperfine clock transition of bismuth
donors in silicon, we can remove strain broadening and that the addition of ALD
layers left $T_2$ (or temporal inhomogeneities) unchanged in these natural
silicon devices.
