A SILICON GERMANIUM GRADED JUNCTIONLESS TRANSISTOR WITH LOW OFF CURRENT

We propose a Ge / Si graded junctionless transistor (JLT) which helps to reduce the band-to-band tunneling current in off-state for highly doped double gate junctionless transistor (DGJLT). In this paper, we show that there is large band-to-band tunneling (BTBT) current in off-state of silicon-channel and germanium-channel DGJLT, which causes increase in the off-state leakage current by several orders. With the help of band-gap engineering, we found that by using Ge / Si graded channel DGJLT off-state band-to-band tunneling current can be reduced. It is also observed that there is large deviation in the off-state leakage current with variation of drain voltage for Si and Ge body DGJLT, which reduces device stability. It is found that in Ge / Si graded DGJLT variation off-state leakage current with drain voltage is controlled. In Si and Ge , DGJLT electrons from the valence band of the channel tunnel to the conduction band of drain leaves holes which causes increased hole concentration in the channel creating parasitic 'BJT'.

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Comparative Study on Off-State Breakdown Characteristics in Nanowire Junctionless and Inversion Mode Multiple Gate MOSFET

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.684.295 ◽

2013 ◽

Vol 684 ◽

pp. 295-298

Author(s):

Seung Min Lee ◽

Hyun Jun Jang ◽

Jong Tae Park

Keyword(s):

Comparative Study ◽

Leakage Current ◽

Tunneling Current ◽

Gate Bias ◽

Inversion Mode ◽

3 Dimensional ◽

Breakdown Mechanism ◽

Band To Band Tunneling ◽

State Breakdown ◽

And Inversion

A comparative study on off-state breakdown characteristics in nanowire JL and IM multiple gate MOSFETs has been performed for different gate bias voltages and fin widths. In order to understand the drain breakdown mechanism with different transistor structures, the device was simulated using the 3-dimensional ATLAS software. The band-to-band tunneling current and the gate-induced-drain-leakage current trigger the off-state breakdown in JL transistor and IM transistor, respectively. From experiment and simulation, the off-state breakdown voltage is lower in JL transistor than in IM transistor. As the gate is biased more negatively, the off-state breakdown voltages are increased in JL and IM transistors.

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Electrical Characteristics of Large Chip-Size 3.3 kV SiC-JBS Diodes

Materials Science Forum ◽

10.4028/www.scientific.net/msf.740-742.881 ◽

2013 ◽

Vol 740-742 ◽

pp. 881-886 ◽

Cited By ~ 8

Author(s):

Hiroyuki Okino ◽

Norifumi Kameshiro ◽

Kumiko Konishi ◽

Naomi Inada ◽

Kazuhiro Mochizuki ◽

...

Keyword(s):

Electric Field ◽

Schottky Barrier ◽

Leakage Current ◽

Reverse Current ◽

Tunneling Current ◽

Leakage Currents ◽

Reverse Leakage Current ◽

Low Leakage ◽

Chip Size ◽

Barrier Metal

The reduction of reverse leakage currents was attempted to fabricate 4H-SiC diodes with large current capacity for high voltage applications. Firstly diodes with Schottky metal of titanium (Ti) with active areas of 2.6 mm2 were fabricated to investigate the mechanisms of reverse leakage currents. The reverse current of a Ti Schottky barrier diode (SBD) is well explained by the tunneling current through the Schottky barrier. Then, the effects of Schottky barrier height and electric field on the reverse currents were investigated. The high Schottky barrier metal of nickel (Ni) effectively reduced the reverse leakage current to 2 x 10-3 times that of the Ti SBD. The suppression of the electric field at the Schottky junction by applying a junction barrier Schottky (JBS) structure reduced the reverse leakage current to 10-2 times that of the Ni SBD. JBS structure with high Schottky barrier metal of Ni was applied to fabricate large chip-size SiC diodes and we achieved 30 A- and 75 A-diodes with low leakage current and high breakdown voltage of 4 kV.

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3 kV Normally-Off 4H-SiC Buried Gate Static Induction Transistors (SiC-BGSITs)

Materials Science Forum ◽

10.4028/www.scientific.net/msf.778-780.899 ◽

2014 ◽

Vol 778-780 ◽

pp. 899-902 ◽

Cited By ~ 2

Author(s):

Akio Takatsuka ◽

Yasunori Tanaka ◽

Koji Yano ◽

Norio Matsumoto ◽

Tsutomu Yatsuo ◽

...

Keyword(s):

Leakage Current ◽

Leakage Current Density ◽

Current Density ◽

Threshold Voltage ◽

Room Temperature ◽

Fabrication Process ◽

Drain Voltage ◽

Static Induction Transistors ◽

Static Induction

3 kV normally-off SiC-buried gate static induction transistors (SiC-BGSITs) were fabricated by using an innovative fabrication process that was used by us previously to fabricate 0.7–1.2 kV SiC-BGSITs. The fabricated device shows the lowest specific on-resistance of 9.16 mΩ·cm2, compared to all other devices of the same class. The threshold voltage of this device was 1.4 V at room temperature and was maintained at values more than 1 V with normally-off characteristics at 200 °C. The device can block drain voltage of 3 kV with a leakage current density of 6.9 mA/cm2.

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