Effects of N2O Anneal on Channel Mobility of 4H-SiC MOSFET and Gate Oxide Reliability

2005 ◽  
Vol 483-485 ◽  
pp. 697-700 ◽  
Author(s):  
Keiko Fujihira ◽  
Yoichiro Tarui ◽  
Kenichi Ohtsuka ◽  
Masayuki Imaizumi ◽  
Tetsuya Takami
Keyword(s):  
Field Effect ◽  
Gate Oxide ◽  
Field Effect Mobility ◽  
Channel Mobility ◽  
Oxide Reliability ◽  
Anneal Temperature

The effect of N2O anneal on channel mobility of inversion-type 4H-SiC n-channel MOSFET has been systematically investigated. It is found that the mobility increases with increasing anneal temperature from 900 to 1150°C. The highest field effect mobility of 30 cm2/Vs is achieved by 1150°C anneal for 3 h, which is about 20 times higher than that for non-annealed MOSFET. In order to investigate the oxide reliability, TDDB measurement has been performed on SiO2 grown on n-type 4H-SiC. The oxide lifetime is found to be drastically improved by N2O anneal.

Effect of Gate Wet Reoxidation on Reliability and Channel Mobility of Metal-Oxide-Semiconductor Field-Effect Transistors Fabricated on 4H-SiC(000-1)

2008 ◽  
Vol 600-603 ◽  
pp. 791-794 ◽  
Author(s):  
Takuma Suzuki ◽  
Junji Senzaki ◽  
Tetsuo Hatakeyama ◽  
Kenji Fukuda ◽  
Takashi Shinohe ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Field Effect ◽  
Dielectric Breakdown ◽  
Field Effect Transistors ◽  
Gate Oxide ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Channel Mobility ◽  
Time Dependent Dielectric Breakdown ◽  
Oxide Reliability

The channel mobility and oxide reliability of metal-oxide-semiconductor field-effect transistors (MOSFETs) on 4H-SiC (0001) carbon face were investigated. The gate oxide was fabricated by using dry-oxidized film followed by pyrogenic reoxidation annealing (ROA). Significant improvements in the oxide reliability were observed by time-dependent dielectric breakdown (TDDB) measurement. Furthermore, the field-effect inversion channel mobility (μFE) of MOSFETs fabricated by using pyrogenic ROA was as high as that of conventional 4H-SiC (0001) MOSFETs having the pyrogenic-oxidized gate oxide. It is suggested that the pyrogenic ROA of dry oxide as a method of gate oxide fabrication satisfies both channel mobility and oxide reliability on 4H-SiC (0001) carbon-face MOSFETs.

Effect of Graphite Cap for Implant Activation on Inversion Channel Mobility in 4H-SiC MOSFETs

2009 ◽  
Vol 615-617 ◽  
pp. 773-776 ◽  
Author(s):  
Harsh Naik ◽  
K. Tang ◽  
T. Paul Chow
Keyword(s):  
Low Temperature ◽  
Carrier Concentration ◽  
Threshold Voltage ◽  
Hall Mobility ◽  
Field Effect ◽  
Gate Oxide ◽  
Subthreshold Slope ◽  
Field Effect Mobility ◽  
Channel Mobility ◽  
Inversion Channel

The effects of using a graphite capping layer during implant activation anneal on the performance of 4H-SiC MOSFETs has been evaluated. Two sets of samples, one with the graphite cap and another without, with a gate oxide process consisting of a low-temperature deposited oxide followed by NO anneal at 1175°C for 2hrs were used for characterization. Various device parameters, particularly threshold voltage, subthreshold slope, field-effect mobility, inversion sheet carrier concentration and Hall mobility have been extracted for the two processes.

High Field Effect Mobility in 6H-SiC MOSFET with Gate Oxides Grown in Alumina Environment

2005 ◽  
Vol 483-485 ◽  
pp. 837-840 ◽  
Author(s):  
Fredrik Allerstam ◽  
G. Gudjónsson ◽  
H.Ö. Ólafsson ◽  
Einar Ö. Sveinbjörnsson ◽  
T. Rödle ◽  
...  
Keyword(s):  
Field Effect ◽  
Field Effect Transistors ◽  
Gate Oxide ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Field Effect Mobility ◽  
Gate Oxides ◽  
Channel Mobility ◽  
Inversion Channel ◽  
Peak Field

Lateral inversion channel metal-oxide-semiconductor field-effect transistors (MOSFETs) were manufactured on 6H-SiC and two gate oxidation recipes were compared. In one case the gate oxide was grown in N2O using quartz environment. The resulting peak field-effect mobility was µFE=43 cm2/Vs. In the other case the gate oxide was grown in oxygen using alumina environment and the resulting peak field-effect mobility was µFE=130 cm2/Vs. Oxidizing in an environment made from sintered alumina introduces contaminants into the oxide that effect the oxidation in several^ways. The oxidation rate is increased and the resulting SiC/SiO2 interface allows higher inversion channel mobility.

High-Mobility SiC MOSFETs with Alkaline Earth Interface Passivation

2016 ◽  
Vol 858 ◽  
pp. 671-676 ◽  
Author(s):  
Daniel J. Lichtenwalner ◽  
Vipindas Pala ◽  
Brett A. Hull ◽  
Scott Allen ◽  
John W. Palmour
Keyword(s):  
Nitric Oxide ◽  
Field Effect ◽  
Alkaline Earth ◽  
Phonon Scattering ◽  
Breakdown Strength ◽  
Field Effect Transistors ◽  
Oxide Semiconductor ◽  
Field Effect Mobility ◽  
Channel Mobility ◽  
Alkaline Earth Elements

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.

Process Optimisation for 4H-SiC MOSFET Applications

2006 ◽  
Vol 527-529 ◽  
pp. 1051-1054 ◽  
Author(s):  
Caroline Blanc ◽  
Dominique Tournier ◽  
Phillippe Godignon ◽  
D.J. Brink ◽  
Véronique Soulière ◽  
...  
Keyword(s):  
Field Effect ◽  
Oxidation Process ◽  
Gate Oxide ◽  
Process Optimisation ◽  
Field Effect Mobility ◽  
Oxide Formation ◽  
Step Procedure ◽  
P Type ◽  
Peak Value ◽  
Gas Precursor

We report on 4H-SiC MOSFET devices implemented on p-type <11-20>-oriented epitaxial layers, using a two-step procedure for gate oxide formation. First is a thin, dry, thermal SiO2 layer grown at 1050°C for 1 hour. Next, is a thick (50 nm) layer of complementary oxide deposited by PECVD using TEOS as gas precursor. With respect to the standard thermal oxidation process, this results in much improvement of the field effect mobility. For the best samples, we find a peak value in the range of 330 cm2/Vs while, on the full wafer, an average mobility of about 160 cm2/Vs is found. Up to now, this is one of the best results ever reported for 4H-SiC MOSFETs.

Gamma Irradiation Effects on 4H-SiC MOS Capacitors and MOSFETs

2006 ◽  
Vol 527-529 ◽  
pp. 1063-1066 ◽  
Author(s):  
Ayayi Claude Ahyi ◽  
S.R. Wang ◽  
John R. Williams
Keyword(s):  
Field Effect ◽  
Gamma Dose ◽  
Interface Traps ◽  
Valence Band Edge ◽  
Field Effect Mobility ◽  
Irradiation Effects ◽  
Mos Capacitors ◽  
Channel Mobility ◽  
Radiation Induced ◽  
Radiation Tolerant

The effects of gamma radiation on field effect mobility and threshold voltage have been studied for lateral n-channel 4H-SiC MOSFETs passivated with nitric oxide. MOS capacitors (n and p) and n-channel lateral MOSFETs were irradiated unbiased (floating contacts) for a total gamma dose of 6.8Mrad (Si). The MOS capacitors were used to study the radiation-induced interface traps and fixed oxide charge that affect the performance of the MOSFETs. Radiationinduced interface traps were observed near the SiC valence band edge and just above mid-gap, and field effect channel mobility was reduced by 18-20% following irradiation. Even so, 4HMOSFETs appear to be more radiation tolerant than Si devices.

Field Effect Mobility in n-Channel Si Face 4H-SiC MOSFET with Gate Oxide Grown on Aluminium Ion-Implanted Material

2005 ◽  
pp. 833-836
Author(s):  
G. Gudjónsson ◽  
H.Ö. Ólafsson ◽  
Fredrik Allerstam ◽  
Per Åke Nilsson ◽  
Einar O. Sveinbjörnsson ◽  
...  
Keyword(s):  
Field Effect ◽  
Gate Oxide ◽  
Field Effect Mobility ◽  
Aluminium Ion ◽  
Ion Implanted

High field-effect mobility in n-channel Si face 4H-SiC MOSFETs with gate oxide grown on aluminum ion-implanted material

2005 ◽  
Vol 26 (2) ◽  
pp. 96-98 ◽  
Author(s):  
G. Gudjonsson ◽  
H.O. Olafsson ◽  
F. Allerstam ◽  
P.-A. Nilsson ◽  
E.O. Sveinbjornsson ◽  
...  
Keyword(s):  
Field Effect ◽  
High Field ◽  
Gate Oxide ◽  
Field Effect Mobility ◽  
Aluminum Ion ◽  
Ion Implanted

Influence of Post-Implantation Annealing Temperature on MOSFET Performance and Oxide Reliability

2013 ◽  
Vol 740-742 ◽  
pp. 703-706
Author(s):  
Michael Grieb ◽  
Stefan Noll ◽  
Dick Scholten ◽  
Martin Rambach
Keyword(s):  
Applied Field ◽  
Field Effect ◽  
Annealing Temperature ◽  
Annealed Sample ◽  
Field Effect Mobility ◽  
Oxide Reliability ◽  
Order Of Magnitude ◽  
Maximum Field ◽  
Post Implantation

In the present work, we studied the influence of the post-implantation annealing temperature on the performance and oxide reliability of lateral 4H-SiC MOSFETs. The maximum field effect mobility of the MOSFETs at 25°C decreases from 22.4cm2/Vs to 17.2cm2/Vs by increasing annealing temperature from 1600°C to 1800°C. Respectively, the measured meantime to failure is about one order of magnitude higher for the 1700°C annealed sample at an applied field of 8.5MV/cm compared to the 1600°C and 1800°C annealed samples.

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