Trap Depth Extraction using New Equation considering Tunneling Mechanism in Gate-Induced Drain Leakage Random Telegraph Noise

Abstract

As device continue to scale down, the effect of an individual defect on device performance and reliability becomes important issue. In metal-oxide-semiconductor field-effect-transistor (MOSFET), random-telegraph-noise (RTN) occur due to random trapping and de-trapping of charges into the trap located in the gate oxide or at Si/SiO2 interfaces. Until a recent day, RTN researches have mainly focused on RTN in channel and gate leakage current in MOSFET. However, these days, RTN in gate-induced drain leakage (GIDL) current has been analyzed because GIDL current is a significant component of leakage current in dynamic random access memory (DRAM) cell transistor. And, it has been deeply related to variable retention time (VRT) phenomenon. GIDL current is composed of band-to-band tunneling and trap-assisted tunneling in gate/drain overlapped region when there is enough bias between gate and drain. In order to deeply understand trap causing of RTN in GIDL current, it is necessary to characterize the traps leading to current fluctuation. In this paper, by using the conventional equation, we extract location and energy level of oxide traps causing of four-level RTN in GIDL current. Through experiment, we apply coulomb energy theory in order to extract capture cross section in both traps. Also, by using lattice coordinate reconfiguration, we explain electron trapping process. And, bias dependency of capture cross section is explained by applying potential barrier lowering. Using extracted capture cross section and considering tunneling mechanism, we derive new equation explained electron capture process, well.