In this paper, the reliability properties of bandgap-engineered SONOS (BE-SONOS) devices with various processing methods are extensively studied. BE-SONOS employs a multilayer O1/N1/O2/N2/O3 stack, ...where O1/N1/O2 serves as a bandgap-engineered tunneling barrier that provides an efficient hole-tunneling erase but eliminates the direct-tunneling leakage. BE-SONOS can overcome the fundamental limitation of the conventional SONOS, for which fast erase speed and good data retention cannot be simultaneously achieved. In this paper, a comprehensive understanding of BE-SONOS reliability is reported, including the processing effects of the critical ONO barrier (O1/N1/O2), the trapping layer (N2), and the top blocking oxide (O3). Moreover, the capability of dielectric scaling is also evaluated. Lower P/E voltages, good P/E cycling endurance, and data retention are maintained when N2 and O3 are further scaled to 60 . The results in this paper provide design and processing guidelines for optimizing the performance and reliability of BE-SONOS flash memory devices.
Two types of addressable failure site test structures are developed. In-house program is coded to extract the electrical information and simulate the failure mode. A complete set of test structure ...modules for 0.25 um logic backend of line process is implemented in a test chip of 22/spl times/6.6 mm/sup 2/. By using the novel test structure, the yield analysis and defect tracking of BEOL process development as well as low-k Fluorinated SiO/sub 2/ (FSG) process optimization are demonstrated.
This work describes the optimization of low-k dielectric process and evaluation of yield impact by using back end of line (BEOL) test structures. Three splits of the low-k dielectric process were ...compared with high-density-plasma un-doped-silicon-glass (HDP-USG) process and are electrically characterized with the test structures of the BEOL unit process and integration process parameter extraction. The interconnect capacitance is used as the optimization criteria of low-k dielectric process and the yield impact is reviewed for the concern of manufacturing.
