This paper explores a possible design for a CMOS compatible, athermal, optical waveguide. The design explored is a slot waveguide with light guided in the low index material. A design paradigm is proposed which shows the relationship between cross-sectional parameters and their impact on both the effective index of refraction and the thermo-optic coefficient of the device. Two materials choices were explored to serve as the low index material, poly(ether imide) (PI) and poly(methyl methacrylate) (PMMA). The slot waveguide with PI as the low index material had a simulated, device thermo-optic coefficient of -8.5 x 10-4K-1, and the slot waveguide with PMMA as the low index material had a simulated, device thermo-optic coefficient of 1.7 x 10-5K-1.