Understanding how 4H-SiC wafers deform and fracture under an applied load is fundamentally important for the semiconductor industry. Cracks inevitably generate during wafer thinning and die sawing, which can significantly impact device reliability. Nanoindentation is a versatile methodology that does not involve microfabrication, allowing for the study of hardness or Young’s modulus at different scales. It also enables the determination of fracture toughness and the identification of consequent plastic defects or crystallographic transitions. In this study, a series of indentation tests were conducted to determine the Young's modulus (E), hardness (H), and fracture toughness (K_IC) of 6-inch and 8-inch 4H-SiC wafers. The characterizations were performed at both room temperature and high temperature using the Anton Paar NHT3 and UNHT3 HTV indentation apparatus. A diamond Berkovich tip with a radius of …