A flash memory operates on the principle of storing charges in the floating gate of a MOSFET, as depicted in Fig. 2.1a . A floating gate stores the charge carriers with the application of proper biases and voltages across gate, source, and drain. The charge gets transported via tunnel oxide under the influence of quantum mechanical tunneling. The charge is stored even after the voltages are removed. Subsequently, alteration to two distinct values, 0 for erased state and 1 for programmed state (Fig. 2.1b), evaluates the amount of charge stored in a floating gate.