Investigation of Random Telegraph Signal with PD SOI MOSFETs

Abstract

A novel method, called random telegraphy signal (RTS), was constructed to characterize the gate oxide quality and reliability of metal-oxide-semiconductor field-effect-transistors (MOSFETs). With the aggressive scaling of device size, drain current RTS (I D -RTS) become a critical role in carrier transport of MOSFETs. Besides, RTS in gate leakage current (I G -RTS) was denoted as the other new method to understand property of gate oxide. Recently, the study of RTS has also been made in MOSFETs with metal gate and high dielectric constant (metal gate/high-k). However, the RTS in partial depleted silicon-on-insulator MOSFETs (PD SOI MOSFETs) has not comprehensively been studied yet. This paper investigates RTS characteristics in PD SOI MOSFETs. IntroductionSilicon on insulator (SOI) MOSFETs have been attracted huge attention recently because of it lower power consumption, good soft-error immunity, increased circuit packing density and absence of CMOS latch-up (1-5). However, the self-heating effect (6-7) and floating body effect (FBE) (9) are the inherent disadvantages in SOI devices. In conventional FBE is attributed to the excess hole were generated by impact ionization in saturation region with floating body condition. The new FBE is in linear region, called gate-induced floating-body effect (GIFBE) due to the aggressive scaling gate oxide thickness induced by gate tunneling current (10-12, 25). Similarly, when device scale down to deep sub-micrometer the random telegraph noise (RTN) or so-called random telegraph signal (RTS) will be observed and influence device dynamic performance (8,22). The RTS phenomenon is commonly related to a carrier capture and emission behaviors. Recently, RTS has been considered as a major concern in scaling digital device because fluctuation of drain current amplitude (ΔI D ) will disturb analysis of signal (13-15). In the deep sub-micrometer MOSFETs device, it is possible to exist one or few oxide traps near the SiO2/Si interface which were distributed over the vicinity of Si surface Fermi level. These traps can be investigated by RTS (16). The high and low level states of drain current (I D ) vary randomly with time, which correspond to the carrier capture and emission at an oxide trap near the SiO2/Si interface. The average time at high level state of drain current corresponds to average capture time < τ c > which means how long will carrier be captured into the trap. On the other hand, the average time at low level state of drain current corresponds to average emission time < τ e > represent how

Investigation of Lateral Trap Position by Random Telegraph Signal Analysis in Moderate Inversion in n-Channel MOSFETs

“…This low current state has been previously shown to be due to both electron trapping and carrier mobility fluctuation. [12][13][14] In addition, previous research has identified two conditions causing mobility fluctuation through Coulombic scattering, either by a single positively or negatively charged trap. 17 In the presence of either a positive charge only without electron trapping (donor type trap) or a negative charge only due to electron trapping (acceptor type trap), Coulombic scattering will occur.…”

“…[7][8][9][10] With the scaling down of metal-oxidesemiconductor field-effect transistors (MOSFETs), random telegraph signal (RTS) have become a major issue that has influenced performance of MOSFETs. [11][12][13][14][15][16][17] The RTS phenomenon is commonly related to the behaviors of a carrier that has been captured and emitted by the oxide trap. Additionally, the operating region of MOSFETs is often chosen in the moderate inversion region due to the need for low power consumption in analog circuits.…”

A Method to Determine the Located Region of Lateral Trap Position by Analysis of Three-Level Random Telegraph Signals in n-MOSFETs

“…When devices are scaled down to deep sub-micrometer, the random telegraph signal (RTS) becomes a major issue and influences the performance of MOSFETs. [10][11][12][13] The RTS phenomenon is commonly caused by a carrier that has been captured and emitted by an oxide trap. Although researches on lateral trap position determined by 2-level channel current RTS (2-RTS) have been previously reported, [13][14][15] there are few reports that study the trap position in multilevel RTS.…”