| The increasing miniaturization of portable electronics, application of electronic systems for deep-space exploration, and the advent of nuclear terrorism have created the need for a high-speed, low-power, high-density non-volatile semiconductor memory (NVSM) capable of long-term data retention under heavy radiation doses. This dissertation characterizes polysilicon-oxide-nitride-oxide-silicon (SONOS) transistors, and proposes, characterizes, and models a device derived from the SONOS technology, the substrate injection nitride based (SNROM) device, to meet the future requirements of space and military systems.; This research characterizes novel short-channel substrate-injection nitride-based (SNROM) transistors (10 x 0.22 mum) fabricated with a 36A-thick tunnel oxide, 30A silicon nitride, and a 36A blocking oxide as the gate dielectric. The thick tunnel oxide prevents tunneling of electrons and holes through the gate dielectric and allows the transistor to be programmed using hot electron and hole injection. This research programs SNROM transistors to produce a 2-volt memory window. The device is written using channel initiated secondary electron injection (CHISEL) by applying 3V to the gate, 2.5V to the drain, and -4V to the bulk for 5ms. The device is erased using hot hole injection by applying -7V to the gate and 4V to the drain for 5ms. The programmed transistor surpasses the 10-year retention requirement with a 0.5V memory window at the 10-year mark. The CHISEL injection mechanism is characterized and modeled by extrapolating the threshold voltage shift, trapped charge, and injected current, from the reduction in channel current during programming. In addition, the impact ionization current is measured at the drain terminal and correlated with the current injected into the ONO gate insulator.; Additionally, electrical characterization is performed on conventional SONOS transistors, with an emphasis on programming efficiency, endurance, and data retention. An acceleration factor is presented to linearly extrapolate 10-year retention from high temperature measurements. This dissertation demonstrates the ability of current conventional SONOS transistors to meet space and military system requirements and presents an innovative SNROM structure as a low-power, high-density NVSM for future applications. |
