Anomalous flatband voltage shift of AlFxOy/Al2O3 MOS capacitors: A consideration on dipole layer formation at dielectric interfaces with different anions

ABSTRACTIn this work, we studied the electrical and thermal stability of Ru and RuO2 electrode on Y-silicate dielectrics in contrast to ZrO2 and Al2O3 dielectrics. Very low resistivity Ru and rutile stoichiometric RuO2 films, deposited via reactive sputtering, were evaluated as gate electrodes on ultrathin Y-silicate, ZrO2 and Al2O3 films for Si-MOS devices. Thermal and chemical stability of the electrodes was studied at annealing temperatures up to 800°C in N2 and subsequently forming gas anneal. XRD and XPS were measured to study grain structure and interface reactions. The morphology of the films was tested by atomic force microscopy (AFM). Electrical properties were evaluated via MOS capacitors. The role of oxygen inside dielectrics was studied by comparing equivalent oxide thickness change as a function of annealing temperature for capacitors with Y-silicate, ZrO2and Al2O3 dielectrics. Good stability of Ru and RuO2 gate electrodes on all dielectrics studied was found. Flatband voltage and gate current as a function of annealing temperature was also studied. It was found that capacitors with Y-silicate after high-temperature anneal had less positive flatband voltage shift than ZrO2 and Al2O3. For capacitors with Ru gate electrode, the significant flatband voltage shift after high temperature anneal could be partially removed by a forming gas anneal.

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Positive flatband voltage shift in phosphorus doped SiO2/N-type 4H-SiC MOS capacitors under high field electron injection

Journal of Physics D Applied Physics ◽

10.1088/1361-6463/ab41dc ◽

2019 ◽

Vol 52 (50) ◽

pp. 505102

Author(s):

M I Idris ◽

M H Weng ◽

A Peters ◽

R J Siddall ◽

N J Townsend ◽

...

Keyword(s):

High Field ◽

Electron Injection ◽

Mos Capacitors ◽

Voltage Shift ◽

Field Electron ◽

Flatband Voltage ◽

Phosphorus Doped

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Flatband Voltage Shift Depending on SiO2/SiC Interface Charges in 4H-SiC MOS Capacitors with AlON/SiO2 Stacked Gate Dielectrics

Materials Science Forum ◽

10.4028/www.scientific.net/msf.858.681 ◽

2016 ◽

Vol 858 ◽

pp. 681-684 ◽

Cited By ~ 1

Author(s):

Takuji Hosoi ◽

Shuji Azumo ◽

Kenji Yamamoto ◽

Masatoshi Aketa ◽

Yusaku Kashiwagi ◽

...

Keyword(s):

Gate Dielectrics ◽

Metal Oxide Semiconductor ◽

Oxide Semiconductor ◽

Aluminum Oxynitride ◽

Equivalent Thickness ◽

Mos Capacitors ◽

Voltage Shift ◽

Interface Charges ◽

Linear Fit ◽

Flatband Voltage

The mechanism of flatband voltage shift in SiC metal-oxide-semiconductor (MOS) capacitors with stacked gate dielectrics consisting of aluminum oxynitride (AlON) layers and SiO2 underlayers was investigated by varying the AlON and SiO2 thicknesses. The flatband voltages of the fabricated capacitors with fixed SiO2 underlayer thicknesses were almost independent of the AlON thickness, indicating the negligible charges in AlON layer. On the other hand, when varying SiO2 underlayer thickness, the flatband voltage decreased with an increase in capacitance equivalent thickness (CET), and the slope of their linear fit was comparable to that for SiC MOS capacitors without AlON layer. These observations can be well explained by assuming interface charges at AlON/SiO2 interface with an amount comparable, but a polarity opposite to, those at SiO2/SiC interface.

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The time dependence of the flatband voltage shift of MOS capacitors caused by the injection of minority carriers from Si into SiO2

phys stat sol (a) ◽

10.1002/pssa.2210510139 ◽

1979 ◽

Vol 51 (1) ◽

pp. K9-K11

Author(s):

B. Joseph

Keyword(s):

Time Dependence ◽

Mos Capacitors ◽

Voltage Shift ◽

Flatband Voltage ◽

Minority Carriers

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Study on Dipole Layer Formation between Two Oxides : Experimental Evidences and Possible Models

MRS Proceedings ◽

10.1557/opl.2011.1519 ◽

2011 ◽

Vol 1331 ◽

Author(s):

Koji Kita ◽

Akira Toriumi

Keyword(s):

Potential Barrier ◽

Electric Potential ◽

Driving Force ◽

Areal Density ◽

Density Difference ◽

Layer Formation ◽

Metal Insulator ◽

Metal Insulator Semiconductor ◽

Dipole Layer ◽

Flatband Voltage

ABSTRACTHetero-interface between two oxides sometimes forms a dipole layer which is experimentally observable macroscopically, as an electric potential barrier at the interface. Investigation of the flatband voltage shift of the metal-insulator-semiconductor capacitors with bilayer oxides as the insulator is suitable to characterize the dipole formation at the interface of two oxides. A model to explain the driving force to form the dipole is discussed by taking account of the areal density difference of oxygen atoms at the interface, which should be a guideline to predict both the direction and magnitude of the interface dipoles. Based on this model the requirement for the oxides to form the dipoles is also discussed.

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Experimental Identification of Extra Type of Charges at SiO2/SiC Interface in 4H-SiC

Materials Science Forum ◽

10.4028/www.scientific.net/msf.645-648.519 ◽

2010 ◽

Vol 645-648 ◽

pp. 519-522 ◽

Cited By ~ 2

Author(s):

Harsh Naik ◽

Z. Li ◽

T. Paul Chow

Keyword(s):

High Temperature ◽

Temperature Dependence ◽

Processing Conditions ◽

Mos Capacitors ◽

Voltage Shift ◽

Experimental Identification ◽

Uv Illumination ◽

Fixed Charges ◽

Flatband Voltage

High temperature C-V characterization with and without UV illumination has been performed on n-type 4H-SiC MOS capacitors fabricated using different processing conditions to extract various types of interfacial charges. An anomalous positive flatband voltage shift with temperature has been observed in most of the SiC MOS capacitors measured. We have experimentally identified an extra type of fixed charges at the 4H-SiC/SiO2 interface from the temperature dependence of the flatband voltage, particularly under UV illumination.

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