Influences of Plasma Processed Interface Layers on Germanium MOS Devices with ALD Grown HfO2

2007 ◽  
Vol 996 ◽  
Author(s):  
Takuya Sugawara ◽  
Raghavasimhan Sreenivasan ◽  
Yasuhiro Oshima ◽  
Paul C. McIntyre
Keyword(s):  
Electrical Properties ◽  
Interface Layer ◽  
Hafnium Dioxide ◽  
Passivation Layer ◽  
Oxide Semiconductor ◽  
Flat Band ◽  
Mos Capacitors ◽  
Mos Devices ◽  
Interface Layers ◽  
Silicon Based

AbstractGermanium and hafnium-dioxide (HfO2) stack structures' physical and electrical properties were studied based on the comparison of germanium and silicon based metal-oxide-semiconductor (MOS) capacitors' electrical properties. In germanium MOS capacitor with oxide/oxynitride interface layer, larger negative flat-band-voltage (Vfb) shift compared with silicon based MOS capacitors was observed. Secondary ion mass spectrum (SIMS) characteristics of HfO2-germanium stack structure with germanium oxynitride (GeON) interfacial layer showed germanium out diffusion into HfO2. These results indicate that the germanium out diffusion into HfO2 would be the origin of the germanium originated negative Vfb shift. Using Ta3N5 layer as a germanium passivation layer, reduced Vfb shift and negligible hysteresis were observed. These results suggest that the selection of passivation layer strongly influences the electrical properties of germanium based MOS devices.

From Radiation Induced Leakage Current to Soft Breakdown in Irradiated MOS Devices With Ultrathin Gate Oxide

1999 ◽  
Vol 592 ◽  
Author(s):  
M. Ceschia ◽  
A. Paccagnella ◽  
A. Cester ◽  
G. Ghidini ◽  
J. Wyss
Keyword(s):  
Leakage Current ◽  
Ion Irradiation ◽  
High Energy ◽  
Oxide Semiconductor ◽  
Flat Band ◽  
Mos Capacitors ◽  
Mos Devices ◽  
Radiation Induced ◽  
High Energy Ions ◽  
Soft Breakdown

ABSTRACTMetal Oxide Semiconductor (MOS) capacitors with ultra-thin oxides have been irradiated with ionising particles (8 MeV electrons or Si, Ni, and Ag high energy ions), featuring various Linear Energy Transfer (LET) ranging over 4 orders of magnitude. Different oxide fields (Fbias) were applied during irradiation, ranging between flat-band and 3 MV/cm. We measured the DC Radiation Induced Leakage Current (RILC) at low fields (3-6 MV/cm) after electron or Si ion irradiation. RILC was the highest in devices biased at flat band during irradiation. In devices irradiated with higher LET ions (Ni and Ag) we observed the onset of Soft-Breakdown phenomena. Soft-Breakdown current increases with the oxide field applied during the stress.

A Comparison of Mos Devices with In-Situ Boron Doped Polysilicon and Poly Sige Gates Deposited in an Rtcvd System Using S12H6 and B2H6 Gas Mixture

1998 ◽  
Vol 525 ◽  
Author(s):  
M. R. Mirabedini ◽  
V. Z-Q Li ◽  
A. R. Acker ◽  
R. T. Kuehn ◽  
D. Venables ◽  
...  
Keyword(s):  
Flat Band ◽  
Gas Mixture ◽  
Mos Capacitors ◽  
Mos Devices ◽  
Boron Doped ◽  
Depletion Effect ◽  
Polysilicon Films ◽  
Sims Analysis ◽  
Boron Penetration

ABSTRACTIn this work, in-situ doped polysilicon and poly-SiGe films have been used as the gate material for the fabrication of MOS devices to evaluate their respective performances. These films were deposited in an RTCVD system using a Si2H6 and GeH4 gas mixture. MOS capacitors with 45 Å thick gate oxides and polysilicon/poly-SiGe gates were subjected to different anneals to study boron penetration. SIMS analysis and flat band voltage measurements showed much lower boron penetration for devices with poly-SiGe gates than for devices with polysilicon gates. In addition, C-V measurements showed no poly depletion effects for poly-SiGe gates while polysilicon gates had a depletion effect of about 8%. A comparison of resistivities of these films showed a low resistivity of 1 mΩ-cm for poly-SiGe films versus 3 mΩ-cm for polysilicon films after an anneal at 950 °C for 30 seconds.

Effect of Interfacial Localization of Phosphorus on Electrical Properties and Reliability of 4H-SiC MOS Devices

2013 ◽  
Vol 740-742 ◽  
pp. 695-698 ◽  
Author(s):  
Tsuyoshi Akagi ◽  
Hiroshi Yano ◽  
Tomoaki Hatayama ◽  
Takashi Fuyuki
Keyword(s):  
Interface State ◽  
State Density ◽  
Oxide Semiconductor ◽  
Conduction Band Edge ◽  
Mos Capacitors ◽  
Mos Devices ◽  
Device Properties ◽  
Phosphorus Doped ◽  
Post Deposition ◽  
Mos Device

Metal-oxide-semiconductor (MOS) capacitors with phosphorus localized near the SiO2/SiC interface were fabricated on 4H-SiC by direct POCl3treatment followed by SiO2deposition. Post-deposition annealing (PDA) temperature affected MOS device properties and phosphorus distribution in the oxide. The sample with PDA at 800 °C showed narrow phosphorus-doped oxide region, resulting in low interface state density near the conduction band edge and small flatband voltage shift after FN injection. The interfacial localization of phosphorus improved both interface properties and reliability of 4H-SiC MOS devices.

Direct Observation of Dielectric Breakdown Spot in Thermal Oxides on 4H-SiC(0001) Using Conductive Atomic Force Microscopy

2010 ◽  
Vol 645-648 ◽  
pp. 821-824 ◽  
Author(s):  
Kohei Kozono ◽  
Takuji Hosoi ◽  
Yusuke Kagei ◽  
Takashi Kirino ◽  
Shuhei Mitani ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Dielectric Breakdown ◽  
Oxide Semiconductor ◽  
Conductive Atomic Force Microscopy ◽  
Mos Capacitors ◽  
Step Bunching ◽  
Force Microscopy ◽  
Line Scan ◽  
Mos Devices ◽  
Atomic Force

The dielectric breakdown mechanism in 4H-SiC metal-oxide-semiconductor (MOS) devices was studied using conductive atomic force microscopy (C-AFM). We performed time-dependent dielectric breakdown (TDDB) measurements using a line scan mode of C-AFM, which can characterize nanoscale degradation of dielectrics. It was found that the Weibull slope () of time-to-breakdown (tBD) statistics in 7-nm-thick thermal oxides on SiC substrates was much larger for the C-AFM line scan than for the common constant voltage stress TDDB tests on MOS capacitors, suggesting the presence of some weak spots in the oxides. Superposition of simultaneously obtained C-AFM topographic and current map images of SiO2/SiC structure clearly demonstrated that most of breakdown spots were located at step bunching. These results indicate that preferential breakdown at step bunching due to local electric field concentration is the probable cause of poor gate oxide reliability of 4H-SiC MOS devices.

On Separating Oxide Charges and Interface Charges in 4H-SiC Metal-Oxide-Semiconductor Devices

2006 ◽  
Vol 527-529 ◽  
pp. 1007-1010 ◽  
Author(s):  
Daniel B. Habersat ◽  
Aivars J. Lelis ◽  
G. Lopez ◽  
J.M. McGarrity ◽  
F. Barry McLean
Keyword(s):  
Room Temperature ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Interface Traps ◽  
Mos Capacitors ◽  
Mos Devices ◽  
Interface Charges ◽  
Flatband Voltage ◽  
Oxide Traps ◽  
P Type

We have investigated the distribution of oxide traps and interface traps in 4H Silicon Carbide MOS devices. The density of interface traps, Dit, was characterized using standard C-V techniques on capacitors and charge pumping on MOSFETs. The number of oxide traps, NOT, was then calculated by measuring the flatband voltage VFB in p-type MOS capacitors. The amount that the measured flatband voltage shifts from ideal, minus the contributions due to the number of filled interface traps Nit, gives an estimate for the number of oxide charges present. We found Dit to be in the low 1011cm−2eV−1 range in midgap and approaching 1012 −1013cm−2eV−1 near the band edges. This corresponds to an Nit of roughly 2.5 ⋅1011cm−2 for a typical capacitor in flatband at room temperature. This data combined with measurements of VFB indicates the presence of roughly 1.3 ⋅1012cm−2 positive NOT charges in the oxide near the interface for our samples.

Processing and Characterization of MOS Capacitors Fabricated on 2°-Off Axis 4H-SiC Epilayers

2016 ◽  
Vol 858 ◽  
pp. 663-666
Author(s):  
Marilena Vivona ◽  
Patrick Fiorenza ◽  
Tomasz Sledziewski ◽  
Alexandra Gkanatsiou ◽  
Michael Krieger ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Interface State ◽  
State Density ◽  
Metal Oxide Semiconductor ◽  
Interface State Density ◽  
Device Fabrication ◽  
Oxide Semiconductor ◽  
Mos Capacitors ◽  
Oxide Breakdown

In this work, the electrical properties of SiO2/SiC interfaces onto a 2°-off axis 4H-SiC layer were studied and validated through the processing and characterization of metal-oxide-semiconductor (MOS) capacitors. The electrical analyses on the MOS capacitors gave an interface state density in the low 1×1012 eV-1cm-2 range, which results comparable to the standard 4°-off-axis 4H-SiC, currently used for device fabrication. From Fowler-Nordheim analysis and breakdown measurements, a barrier height of 2.9 eV and an oxide breakdown of 10.3 MV/cm were determined. The results demonstrate the maturity of the 2°-off axis material and pave the way for the fabrication of 4H-SiC MOSFET devices on this misorientation angle.

Passivation and Generation of States at P-Implanted Thermally Grown and Deposited N-Type 4H-SiC/SiO2 Interfaces

2016 ◽  
Vol 858 ◽  
pp. 697-700 ◽  
Author(s):  
Tomasz Sledziewski ◽  
Heiko B. Weber ◽  
Michael Krieger
Keyword(s):  
Electrical Properties ◽  
Response Time ◽  
Side Effect ◽  
Oxide Semiconductor ◽  
Epitaxial Layers ◽  
Interface Traps ◽  
Semiconductor Interface ◽  
Mos Capacitors ◽  
Thermally Grown Oxides ◽  
Thermally Grown

In this work the effect of phosphorus on the electrical properties of n-type 4H-SiC MOS capacitors is studied. Phosphorus ions are implanted into the epitaxial layers prior to the deposition of SiO2 by PECVD, in shallow depths and at concentrations at the oxide-semiconductor interface in the range of (5 x 1017…1 x 1019) cm-3. Those samples are compared with 31P-implanted 4H-SiC MOS capacitors with thermally grown oxides, which were primarily investigated in the previous work of the authors. It is shown that independently of the oxide technology phosphorus may lead to decrease of the density of interface traps, whose response time to the AC voltage is longer than 1 µs. The side-effect of the implantation of phosphorus is generation of the very fast interface states, which are able to follow the frequencies over 1 MHz.

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