Recovery of the MOSFET and Circuit Functionality After the Dielectric Breakdown of Ultrathin High-$k$ Gate Stacks

Injected Charge to Recovery as a Parameter to Characterize the Breakdown Reversibility of Ultrathin HfSiON Gate Dielectric

“…This phenomenology has strong similarities with the resistive switching (RS) effect [4][5][6], typically observed in MIM structures with a thicker insulator (several tenths of nm) [5] which today is having an increasing interest for its applications in RRAM devices [6]. From the reliability point of view, the existence of two conductivity states indicates that the insulator properties of the dielectric can be at least partially recovered [7,8], and consequently, a partial restoration of the device and circuit functionality is produced [8]. However, a better understanding of the reversibility of the dielectric breakdown phenomenon needs large modelling and characterization efforts [9].…”

“…Initially, IG is high (~400μA) due to the breakdown provoked during the previous CL-RVS, and increases with the stress voltage at each voltage step (BD state). However, after ~420s of S-RVS, when VG=-0.95V, IG suddenly decreases three orders of magnitude, i.e., the dielectric BD recovery (R) is observed, which indicates that the previously 'opened' BD path has been 'closed' [8]. In some cases, as in Figure 3, new recoveries can be observed (R').…”

“…In all cases, the duration of the S-RVS was 1200s. Although the BD reversibility can be observed during constant-voltage stresses as well [8], S-RVS were chosen instead to warrant the BD recovery in a reasonable testing time, because the selection of the voltage at which the recovery can be observed during the stress time is critical. Negative voltage CL-RVS were always applied whereas the polarity of the S-RVS could be either positive or negative.…”

Temperature dependence of the resistive switching-related currents in ultra-thin high-k based MOSFETs

“…3,4 Moreover, it has been shown that when the dielectric switches back from the high conductivity state to the low conductivity state the device performance is partially restored and the circuit lifetime is increased. 5 A change between different conduction states in the dielectric material also characterizes the resistive switching (RS) phenomenon usually observed in metal-insulator-metal/metalinsulator-semiconductor (MIM/MIS) capacitors with a thick insulator (several tenths of a nanometer), which is being widely investigated as the operation principle of resistive random-access-memory (RRAM) nonvolatile memories. This principle can be understood as the formation of a conductive filament that can be closed again, i.e., by destruction of the filament.…”

Resistive switching-like behavior of the dielectric breakdown in ultra-thin Hf based gate stacks in MOSFETs

“…However, several years ago it was shown that in SiO 2 , in some occasions, BD could be reversible [9], i.e., a lower conductivity state could be reached after a BD event. More recently, the presence of two interchangeable conductivity states after BD in MOSFETs with ultrathin Hf based gate dielectric stacks has been reported [10,11], so that the insulator properties of the dielectric can be at least partially recovered [10,12]. However BD reversibility phenomenon in ultrathin dielectrics, as those used in ultrascalled MOSFETs, is not well understood yet and consequently modeling and characterization efforts are needed.…”