  We detail several scientific and engineering innovations which enable the
controlled spalling of 10 - 50 micron thick films of single crystal 4H silicon
carbide (4H-SiC) from bulk substrates. 4H-SiC's properties, including high
thermal conductivity and a wide bandgap, make it an ideal candidate for
high-temperature, high-voltage power electronic devices. Moreover, 4H-SiC has
been shown to be an excellent host of solid-state atomic defect qubits for
quantum computing and quantum networking. Because 4H-SiC single crystal
substrates are expensive (due to long growth times and limited yield),
techniques for removal and transfer of bulk-quality films in the
tens-of-microns thickness range are highly desirable to allow for substrate
reuse and integration of the separated films. In this work we utilize novel
approaches for stressor layer thickness control and spalling crack initiation
to demonstrate controlled spalling of 4H-SiC, the highest fracture toughness
material spalled to date. Additionally, we demonstrate substrate re-use,
bonding of the spalled films to carrier substrates, and explore the spin
coherence of the spalled films. In preliminary studies we are able to achieve
coherent spin control of neutral divacancy ($VV^{0}$) qubit ensembles and
measure a quasi-bulk spin $T_{2}$ of 79.7 $\mu$s in such spalled films.
