In this project I demonstrate use of nanoindenter to characterize the fracture toughness of Si wafers (reproducing research done at other groups). The idea was to expand use of this technique in characterization of other brittle materials being deposited in our lab at that time. The fracture toughness K_IC is not a fundamental property of material and is dependent in this estimate on primarily the crack length. However in reality several factors such as temperature, loading rate, defect concentration, et cetera should affect the fracture toughness which are not captured in the equation used per se. I also use Scanning Probe Microscopy (SPM) instead of more ideal Scanning Electron Microscopy (SEM) to estimate crack length which may cause deviation in final results. The results obtained however seems to be satisfactory but may need further re-confirmation with higher sample size and change of microscopy technique to say at the least.