Nanocrystal (NC) flash memory, going by its competitive performance, has a very promising role in future electronic devices. So knowing how to measure and characterize NC flash memory is an important aspect for developing it for commercial devices. This chapter reviews the progress in the electrical characterizations of silicon (Si) NCs as materials and also in floating gate memory devices. This chapter is mainly divided into four parts. The first will discuss the introduction of Si NCs in flash memory, including structure development of a Si NC floating gate and electrical characteristics of Si NCs in flash memory. In the structure development of a Si NC floating gate, we will introduce the Si NC floating-gate story and preparation of Si NCs for flash memory. In the second part, we will discuss the Si NC

trap center studied by deep-level transient spectroscopy (DLTS). The third one will introduce engineering for improved Si NC flash memory. Special care is taken to discuss in detail DLTS, which is the method used for measuring Si NCs in flash memory and the characterization of the promising role Si NC flash memory. Also, the chapter identifies the challenges Si-NC-based floating-gate memory devices face in the future.