Simulation study of channel mobility and device performance dependence on gate stack in graphene field-effect transistors

2012 ◽  
Vol 100 (11) ◽  
pp. 112104 ◽  
Author(s):  
Weinan Zhu ◽  
Jinyu Zhang ◽  
Zhiping Yu
2017 ◽  
Vol 23 (5) ◽  
pp. 916-925
Author(s):  
Pritesh Parikh ◽  
Corey Senowitz ◽  
Don Lyons ◽  
Isabelle Martin ◽  
Ty J. Prosa ◽  
...  

AbstractThe semiconductor industry has seen tremendous progress over the last few decades with continuous reduction in transistor size to improve device performance. Miniaturization of devices has led to changes in the dopants and dielectric layers incorporated. As the gradual shift from two-dimensional metal-oxide semiconductor field-effect transistor to three-dimensional (3D) field-effect transistors (finFETs) occurred, it has become imperative to understand compositional variability with nanoscale spatial resolution. Compositional changes can affect device performance primarily through fluctuations in threshold voltage and channel current density. Traditional techniques such as scanning electron microscope and focused ion beam no longer provide the required resolution to probe the physical structure and chemical composition of individual fins. Hence advanced multimodal characterization approaches are required to better understand electronic devices. Herein, we report the study of 14 nm commercial finFETs using atom probe tomography (APT) and scanning transmission electron microscopy–energy-dispersive X-ray spectroscopy (STEM-EDS). Complimentary compositional maps were obtained using both techniques with analysis of the gate dielectrics and silicon fin. APT additionally provided 3D information and allowed analysis of the distribution of low atomic number dopant elements (e.g., boron), which are elusive when using STEM-EDS.


2017 ◽  
Vol 16 (1) ◽  
pp. 69-74
Author(s):  
Md Iktiham Bin Taher ◽  
Md. Tanvir Hasan

Gallium nitride (GaN) based metal-oxide semiconductor field-effect transistors (MOSFETs) are promising for switching device applications. The doping of n- and p-layers is varied to evaluate the figure of merits of proposed devices with a gate length of 10 nm. Devices are switched from OFF-state (gate voltage, VGS = 0 V) to ON-state (VGS = 1 V) for a fixed drain voltage, VDS = 0.75 V. The device with channel doping of 1×1016 cm-3 and source/drain (S/D) of 1×1020 cm-3 shows good device performance due to better control of gate over channel. The ON-current (ION), OFF-current (IOFF), subthreshold swing (SS), drain induce barrier lowering (DIBL), and delay time are found to be 6.85 mA/μm, 5.15×10-7 A/μm, 87.8 mV/decade, and 100.5 mV/V, 0.035 ps, respectively. These results indicate that GaN-based MOSFETs are very suitable for the logic switching application in nanoscale regime.


2016 ◽  
Vol 858 ◽  
pp. 671-676 ◽  
Author(s):  
Daniel J. Lichtenwalner ◽  
Vipindas Pala ◽  
Brett A. Hull ◽  
Scott Allen ◽  
John W. Palmour

Alkaline earth elements Sr and Ba provide SiO2/SiC interface conditions suitable for obtaining high channel mobility metal-oxide-semiconductor field-effect-transistors (MOSFETs) on the Si-face (0001) of 4H-SiC, without the standard nitric oxide (NO) anneal. The alkaline earth elements Sr and Ba located at/near the SiO2/SiC interface result in field-effect mobility (μFE) values as high as 65 and 110 cm2/V.s, respectively, on 5×1015 cm-3 Al-doped p-type SiC. As the SiC doping increases, peak mobility decreases as expected, but the peak mobility remains higher for Ba interface layer (Ba IL) devices compared to NO annealed devices. The Ba IL MOSFET field-effect mobility decreases as the temperature is increased to 150 °C, as expected when mobility is phonon-scattering-limited, not interface-trap-limited. This is in agreement with measurements of the interface state density (DIT) using the high-low C-V technique, indicating that the Ba IL results in lower DIT than that of samples with nitric oxide passivation. Vertical power MOSFET (DMOSFET) devices (1200V, 15A) fabricated with the Ba IL have a 15% lower on-resistance compared to devices with NO passivation. The DMOSFET devices with a Ba IL maintain a stable threshold voltage under NBTI stress conditions of-15V gate bias stress, at 150 °C for 100hrs, indicating no mobile ions. Secondary-ion mass-spectrometry (SIMS) analysis confirms that the Sr and Ba remain predominantly at the SiO2/SiC interface, even after high temperature oxide annealing, consistent with the observed high channel mobility after these anneals. The alkaline earth elements result in enhanced SiC oxidation rate, and the resulting gate oxide breakdown strength is slightly reduced compared to NO annealed thermal oxides on SiC.


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