Plasma-induced charging in two bit per cell SONOS memories

UV Total Dose Nonvolatile Sensor Using Fluorine-Treated SOHOS Capacitor Device

“…For UV TD data writing, 100 mW·s/cm 2 TD UV irradiation together with PVS (VG = 20 V) were impinged simultaneously on the F-SOHOS capacitor devices. As illustrated in Figure 2b, the CG-VG curve of F-SOHOS capacitor shifted to the right after UV total dose (here after TD) up to 100 mW·s/cm 2 irradiation under gate PVS 20 V. This indicates that UV TD 100 mW·s/cm 2 irradiation induces a increase of VT (about 4 V) for the F-SOHOS capacitor under gate PVS VG 20 V. This positive VT shift result is in agreement with previous studies [1][2][3].…”

“…But the VT increased more slowly when UV TD larger than 30 mW·s/cm 2 . These experimental results in this study are in agreement with previous studies [1][2][3].…”

“…The positive VT shift is due to an increase in net total negative trapped charges accumulated in the OHO gate dielectric layer after UV TD irradiation under gate PVS 20 V. These radiation-induced positive VT shifts in the UV irradiated F-SOHOS capacitor device under gate PVS 20 V are result from electrons on Si substrate excited by UV photons, and then injected under gate PVS 20V over the SiSiO2 potential barrier into the trapping layer, and finally trapped in the nitride trapping layer of OHO [1][2][3]. UV TD irradiation and gate PVS was applied on the F-SOHOS capacitor device simultaneously for writing data by UV radiation.…”

“…The semiconductor dosimeters offer many advantages, the dose sensing areas of semiconductor dosimeters are very small, and their dose sensitivity can be high in a small constrained space. A silicon-silicon dioxide-hafnium oxidesilicon dioxide-silicon (SOHOS) capacitor device has been shown to be suitable for nonvolatile UV irradiation TD sensor applications [1][2][3]. UV irradiation induces a significant increase in the threshold voltage VT of the SOHOS capacitor device and this UV induced increase in VT for SOHOS capacitor has a strong correlation to UV TD.…”

“…Moreover, the reliability characteristic of VT retention for the SOHOS capacitor device is good, even after 10 years retention. This SOHOS UV TD sensor, has the following two characteristics: (1) The UV TD information can be stored and accumulated in this nonvolatile SOHOS capacitor device permanently, even under data read, data write, and high temperature condition [1][2][3][4][5][6][7][8]; (2) UV TD data in the SOHOS capacitor can be erased to original null state by positive charges injection under gate negative bias stress (hereafter NVS), but it can't be annealed by high temperature [1][2][3][4][5][6][7][8].…”