New concepts in technology- the cloud, big data, internet of things, demand ultra-high density data storage. With the Planar NAND Flash NVM attaining its cell-size scaling limit, alternative memory designs are sought to meet this demand. Among these is the 3D flash memory. It permits the integration of long-retention, ultra-high density cells without compromising device reliability. A challenge of 3D flash is that the vertically-stacked cells require low process temperatures in order not to damage underneath device layers. Unfortunately, most common methods for growing poly-Si require process temperature 600°C. These temperatures stress device structures, increase thermal budget, eliminate low thermal materials as substrates and cause the migration of dopants from their desired locations, thus decreasing the doping density and causing device leakage. This book describes a new low-temperature method of growing poly-Si films at 400°C and the investigations of the possibility of using these films as data storage medium in flash NVM. It also reviews various deposition methods of Si films as well as emerging memory devices.