Time-dependent Dielectric Breakdown Properties Research Articles

Reliability of Passivated and Unpassivated High-k Dielectric/GaAs Metal-Oxide-Semiconductor Capacitors

Metal-oxide-semiconductor (MOS) capacitors were fabricated using zirconium dioxide as a high-k dielectric layer on p-GaAs substrates with and without passivation layers. Ultrathin (1.8 nm) InP and ZnO were used as a passivation layer to prevent Fermi level pinning and regrowth of GaAs-native oxides at the interface between GaAs and ZrO2. The trapping of charge carriers and device reliability were investigated in passivated and unpassivated GaAs MOS capacitors during electrical stress. The improved characteristics in terms of stress-induced interface trap variation, hysteresis voltage, stress induced leakage current, and flat-band voltage have been demonstrated in InP and ZnO passivated MOS devices. Time dependent dielectric breakdown properties were studied in presence of electrical stress. The breakdown time was found to be 1748 and 1703 s in InP and ZnO passivated devices, respectively, however, in unpassivated devices, it was 928 s. The InP passivated GaAs MOS devices show improved electrical and breakdown characteristics over other MOS devices.

Time-dependent dielectric breakdown measurements of porous organosilicate glass using mercury and solid metal probes

Time-dependent dielectric breakdown (TDDB) is one of the major concerns for low-k dielectric materials. During plasma processing, low-k dielectrics are subjected to vacuum ultraviolet photon radiation and charged-particle bombardment. To examine the change of TDDB properties, time-to-breakdown measurements are made to porous SiCOH before and after plasma exposure. Significant discrepancies between mercury and solid-metal probes are observed and have been shown to be attributed to mercury diffusion into the dielectric porosities.

Reliability studies of MOCVD TiSiN and EnCoRe Ta(N)/Ta

Passivated single damascene copper SiO 2 damascene lines were evaluated in combination with TiSiN and Ta(N)/Ta diffusion barriers. Leakage current, breakdown and time-dependent dielectric breakdown properties were investigated on a wafer level basis for temperatures ranging between room temperature and 150 °C. It is found that the leakage performance of the wafers with a TiSiN barrier is better at room temperature, but at 150 °C the performance levels out with Ta(N)/Ta. Time-dependent dielectric breakdown measurements at 150 °C show that the lifetime of the interconnect is higher with the selected Ta(N)/Ta barrier than for TiSiN.

Influence of Native Oxides on the Reliability of Ultrathin Gate Oxide

The influence of wet cleaning processes, such as the SC-1 and H2O2 processes, on the time dependent dielectric breakdown (TDDB) of ultrathin gate oxide was investigated. A large difference in the reliability by wet cleaning processes was observed, especially when an electrode is an anode. The reliability of the gate oxide by the H2O2 process was worse than SC-1. It was found by Fourier transformed infrared attenuated total reflection (FT-IR-ATR) analysis that the amount of structural imperfection of native oxides formed in H2O2 was larger than SC-1. Since stress-induced positive charges which affect the TDDB properties are generated near the anode- side oxide interface, a large amount of structural imperfection in the native oxides formed in H2O2 probably results in a defective thermal oxide surface, leading to an increase in the generation and trapping of positive charge.

Effects of growth temperature on TDDB characteristics of N/sub 2/O-grown oxides

Effects of oxide growth temperature on time-dependent dielectric breakdown (TDDB) characteristics of thin (115 AA) N/sub 2/O-grown oxides are investigated and compared with those for conventional O/sub 2/-grown SiO/sub 2/ films with identical thickness. Results show that TDDB characteristics of N/sub 2/O oxides are strongly dependent on the growth temperature and, unlike conventional SiO/sub 2/, TDDB properties are much degraded for N/sub 2/O oxides with an increase in growth temperature. Large undulations at the Si/SiO/sub 2/ interface, caused by locally retarded oxide growth due to interfacial nitrogen, are suggested as a likely cause of degradation of TDDB characteristics in N/sub 2/O oxides grown at higher temperatures. >