Browsing by Author "Djezzar, B."

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Fast and simple method for estimation and separation of radiation-induced traps in MOSFETs devices
(IEEE, 2011) Nadji, B.; Tahi, H.; Djezzar, B.
In this work, we propose a simple and fast method to estimate the radiation-induced traps in P and N-MOS transistors independently. This method is based on standard current-voltage and Charge Pumping (I(V)-CP) to separate the radiation-induced border-traps (N bt) and true interface-traps (N it), where the radiation-induced oxide-traps (N ot) are extracted classically by measuring the threshold voltage (V th) or Mid-Gap (V mg) voltage shift. The charge pumping (CP) curves are measured using the rise and fall saw-tooth signal for N-and P-MOS transistors respectively, to minimize the border-trap estimation error caused by the difference in the energy band gap scanned by standard I(V) and CP techniques. Emphasis is made on critical comparison between the radiation induced N bt extracted using I(V)-CP and classical method such as OTCP and DTBT. According to experimental data, the I(V)-CP method is more accurate than OTCP and DTBT methods, since it is more sensitive than OTCP method for the extraction of border traps and it can gives all kinds of traps for P and N-MOS transistors separately
Geometric component in constant-amplitude charge-pumping characteristics of LOCOS- and LDD-MOSFET devices
(IEEE, 2011) Tahi, H.; Djezzar, B.; Benabdelmoumen, A.; Nadji, B.
Hot carrier degradation in Triple-RESURF LDMOS with Trenched-Gate
(IEEE, 2021) Houadef, Ali; Djezzar, B.
This work investigates by TCAD simulation the impact of hot carrier degradation (HCD) in an nLDMOS that uses many topological features. The trenched gate and the triple-RESURF used to optimally reduce the device on-resistance (RON) , triggers DC shifts that easily surpass 10%. We show that using such topologies implicates a narrower safe operating area (SOA)
Modeling and simulation of charge-pumping characteristics for LDD-MOSFET devices with LOCOS isolation
(2010) Tahi, H.; Djezzar, B.; Nadji, B.
We propose a model for the so-called constant-amplitude charge-pumping (CP) characteristics, giving the Elliot Gaussian-like CP current curve (ICP-VL) of lightly doped drain (LDD) MOSFET with local oxidation of silicon (LOCOS). This method is based on modulation of the contributing active-channel area (AG) to the ICP-VL curve, depending on the position of the high and low levels of the gate signal voltage. In addition, it allows to separate and clarify the contribution of all MOSFET regions (such as the effective channel, LDD, LOCOS, and LDD subdiffusion under the LOCOS) to the amount of ICP-VL curves. We have simulated this model and compared with experimental CP data. The model shows a very good correlation with experimental ICP-VL curves, particularly for transistors with short channel gate lengths (LG ≤ 1 μm). However, as the channel gate length increases, the model matches only for rising and falling ICP-VL curve edges, corresponding to the contribution of LDD and LOCOS regions, respectively. Moreover, we have demonstrated that the deviation, which was observed between the CP model and experimental data at the maximum plateau of ICP-VL characteristics, depends on the gate pulse fall time and vanishes for large fall time. This difference has been found to behave like a geometric component, since it depends on gate length and fall time and disappears for both short gate lengths and long fall times
Radiation effect evaluation in effective short and narrow channels of LDD transistor with LOCOS isolation using OTCP method
(2010) Tahi, H.; Djezzar, B.; Nadji, B.
In this paper, we have presented a new methodology to take out the local oxidation of silicon (LOCOS) and lightly doped drain (LDD) subdiffusion effects from charge-pumping (CP) curves, leaving only the CP current of the effective channel, in narrow- and short-channel MOSFET transistors. First, we have clarified the contribution of LDD-subdiffusion and LOCOS regions to the CP characteristics by studying the spatial distributions of CP threshold and flatband voltages. We have shown that the maximum CP current is the contribution of pumped current in the effective-channel, LOCOS, and LDD-subdiffusion regions. Second, we have successfully used the oxide-trap CP (OTCP) to extract the radiation-induced oxide trap (??N ot) and interface trap (??N it) in effective short- and narrow-channel transistors. Finally, we have performed a comparison between the OTCP and the capacitance-versus-voltage method
Using oxide-trap charge-pumping method in radiation-reliability analysis of short lightly doped drain transistor
(2010) Djezzar, B.; Tahi, H.
In this paper, a thorough investigation of the application possibilities of the oxide-trap charge-pumping (OTCP) extraction method to evaluate the radiation-induced traps in short lightly doped drain (LDD) transistors is conducted. We have successfully demonstrated that the OTCP is able to determine all kind of traps induced by radiation in short LDD transistors. First, we have presented a methodical approach to take out the LDD effect from CP curves, leaving only the effective channel-length CP. Second, we have extracted the radiation-induced interface, oxide, and border traps for LDD-NMOSFET and LDD-PMOSFET with varied gate length and fixed gate width. Finally, we have performed a comparison between OTCP and subthreshold slop (STS), midgap (MG), dual-transistor CP (DTCP), and DT border trap (DTBT). OTCP method shows perfect agreement with all methods regarding oxide-trap (??N ot) extraction versus gate length. However, it does not correlate with STS and MG for interface trap (??N it) , because the latter methods overestimate ??N it by sensing border trap (??Nbt) as an interface trap. We have observed the same behaviors in the narrow LDD transistors. The OTCP method estimates ??N ot for N- and P-MOSFET separately, while DTCP and DTBT give average density for whole N- and P-MOS devices. Unlike DTCP and DTBT, OTCP can be applied on a single transistor using a single-measurement technique
Why is oxide-trap charge-pumping method appropriate for radiation-induced trap depiction in MOSFET?
(2009) Djezzar, B.; Tahi, H.; Mokrani, A.
Radiation-induced traps, which are generally identified using specific extraction methods, play an important role in the reliability of MOS devices. In this paper, the oxide-trap-based-on-charge-pumping (OTCP) method is used to estimate radiation-induced oxide, interface, and border traps in complementary N- and P-MOS transistors. We emphasize on the critical comparison between the OTCP and classical methods like subthreshold slope (STS), midgap (MG), capacitance-voltage (CV), dual-transistor CP (DTCP), and DT border trap (DTBT), giving a clear insight on the benefits and limitations of OTCP. According to experimental data, the OTCP method is often more accurate than the classical methods. On one side, OTCP offers more accurate densities of radiation-induced interface traps (DeltaN it) and border traps (DeltaN bt), while STS and MG overestimate DeltaN it because both interface and border traps are sensed like interface traps. On the other side, OTCP estimates DeltaN it, DeltaN bt, and oxide trap (DeltaN ot) for N- and P-MOSFETs separately, while DTCP and DTBT give average densities for whole N- and P-MOS devices. Finally, DeltaN ot obtained by OTCP is in excellent agreement with that given by CV. However, they show a slight discrepancy in the DeltaN it extraction