  The design, fabrication, and characterization of low loss ultra-compact bends
in high index (n = 3.1 at {\lambda} = 1550 nm) PECVD silicon rich silicon
nitride (SRN) is demonstrated and utilized to realize efficient, small
footprint thermo-optic phase shifter. Compact bends are structured into a
folded waveguide geometry to form a rectangular spiral within an area of 65 x
65 \mum2 possessing a total active waveguide length of 1.2 mm. The device
features a phase shifting efficiency of 8 mW/{\pi} and a 3 dB switching
bandwidth of 15 KHz. We propose SRN as a promising thermo-optic platform
combining the properties of silicon and silicon stoichiometric nitride
