In this paper, we present a systematic approach to the gallium nitride (GaN) chemical mechanical planarization (CMP) process through evaluating the effect of crystallographic orientation, slurry chemistry and process variables on the removal rate and surface quality responses. A new CMP process and a complementary tool set-up are introduced to enhance GaN material removal rates. The key process variables are studied to set them at an optimal level, while a new slurry feed methodology is introduced in addition to a new tool set up to enable high material removal rates and acceptable surface quality through close control of the process chemistry. It is shown that the optimized settings can significantly improve the material removal rates as compared to the literature findings while simultaneously enabling a more sustainable process and potential removal selectivity against silica. GaN is defined as the silicon of the future based on its adaptability to a wide range of devices including microelectronics and photonics. 1It is used for the high power, high temperature and high frequency microelectronics device manufacturing due to its wide bandgap energy and high electron mobility including heterojunction field effect transistors (HFETs) and its derivatives (Metal Oxide Semiconductor HFETs-MOSHFET and Metal Oxide Semiconductor Double HFETsMOSDHFETs) as a barrier layer, 2 high electron mobility transistors (HEMTs) for power switching with AlGaN/GaN stacking as a buffer layer 3 as well as for the applications for heterojunction bipolar transistors (HBTs) and bipolar junction transistors (BJTs). 4 In addition, GaN is suitable for photonics device manufacturing based on its direct bandgap. It is designed into the light emitting diodes (LEDs) and ultraviolet LED (UVLED) manufacturing as an active region. 5,6 These applications require the polishing and optimal planarization of the GaN layers where CMP is the method of choice due to enabling nano-scale smoothness on the wafer surfaces in addition to enabling material and topographic selectivity through advanced slurry formulations.7 Yet, the main problem in integration of GaN is related to the challenges in its defect free deposition and its hard and brittle nature, which makes it difficult to polish and planarize in an integration scheme without creating surface defectivity, which can be defined as the elevated surface roughness, scratches, local pitting and protrusions, slurry particles and particles from the surroundings that might be left on the wafer surface.The growth of thick and crystalline GaN films is very challenging due to the formation of the threading dislocations between the selected substrate and the GaN interface that can act as the short-circuit leakage paths.1 Furthermore, it is also known that GaN films tend to crack above a critical thickness, which can even lead to the film and the substrate to fracture into separate pieces.8 Many conventional deposition techniques fail to satisfy the defect free deposition of GaN on conventional substrates such as si...