Fixed-charge generation in SiO2/GaN MOS structures by forming gas annealing and its suppression by controlling Ga-oxide interlayer growth

2021 ◽  
Author(s):  
Hidetoshi Mizobata ◽  
Mikito Nozaki ◽  
Takuma Kobayashi ◽  
Takuji Hosoi ◽  
Takayoshi Shimura ◽  
...  
Keyword(s):  
Defect Formation ◽  
Fixed Charge ◽  
Oxide Semiconductor ◽  
Oxide Growth ◽  
Charge Generation ◽  
Mos Devices ◽  
Defect Passivation ◽  
Interface Structures ◽  
Electrical Characterizations ◽  
Mos Structures

Abstract A recent study has shown that anomalous positive fixed charge is generated at SiO2/GaN interfaces by forming gas annealing (FGA). Here, we conducted systematic physical and electrical characterizations of GaN-based metal-oxide-semiconductor (MOS) structures to gain insight into the charge generation mechanism and to design optimal interface structures. A distinct correlation between the amount of FGA-induced fixed charge and interface oxide growth indicated the physical origins of the fixed charge to be defect formation driven by reduction of the Ga-oxide (GaOx) interlayer. This finding implies that, although post-deposition annealing in oxygen compensates for oxygen deficiencies and FGA passivates defect in GaN MOS structures, excessive interlayer GaOx growth leads to instability in the subsequent FGA treatment. On the basis of this knowledge, SiO2/GaOx/GaN MOS devices with improved electrical properties were fabricated by precisely controlling the interfacial oxide growth while taking advantage of defect passivation with FGA.

EPR Study of the Role of Hydrogen in the Defect Formation Upon Heat Treatment of Oxidized SiC

1998 ◽  
Vol 513 ◽  
Author(s):  
P. J. Macfarlane ◽  
M. E. Zvanut
Keyword(s):  
Heat Treatment ◽  
Defect Formation ◽  
Wide Band ◽  
Oxide Semiconductor ◽  
Wide Band Gap ◽  
Paramagnetic Resonance ◽  
Hydrogen Incorporation ◽  
Si Substrates ◽  
Mos Devices ◽  
Dry Heat Treatment

ABSTRACTFor the past several years hydrogen incorporation in metal oxide semiconductor (MOS) devices has been of interest because studies have shown that vacuum annealing of oxidized Si substrates desorbs hydrogen, revealing interfacial defects. Today, in applications that require higher power and/or temperature, Si will likely be replaced with a wide-band-gap semiconductor. For MOS devices, SiC is a leading contender because it can be thermally oxidized to form a SiO2 insulating layer similar to Si. However, the SiC/SiO2 structure potentially contains hydrogen sensitive centers similar to those found in Si/SiO2 structures. Using electron paramagnetic resonance (EPR), we have observed a center 1.8 G wide peak-to-peak at g=2.0026. The center is generated in oxidized SiC that has received a 900° C dry, N2 or O2, post oxidation heat-treatment in which moisture is measured to be less than 1 ppm. Annealing at 900° C in standard Ar containing at least 50 ppm H2O decreases the center's concentration by two orders of magnitude. By comparing results from our study to studies of Si-H and C-H bonds in a-SiC:H [1] and SiC converted graphite [2], we suggest that this center is related to carbon dangling bonds created by the effusion of hydrogen during the dry heat-treatment. We will compare the activation energy for the hydrogen depassivation of our center with that found for other C-H and Si-H systems.

scholarly journals A Model for Neutron Radiation Damage in Metal Oxide Semiconductor (MOS) Structures

2016 ◽  
Vol 706 ◽  
pp. 51-54
Author(s):  
Haider F. Abdul Amir ◽  
Abu Hassan Husin ◽  
Saafie Salleh ◽  
Fuei Pien Chee
Keyword(s):  
Lattice Structure ◽  
Neutron Radiation ◽  
Mean Free Path ◽  
Depletion Region ◽  
Oxide Semiconductor ◽  
Mos Devices ◽  
Single Neutron ◽  
Electron Hole Pair ◽  
Mos Structures

Neutron bombardment on semiconductor material causes defects, one such primary physical effect is the formation of displacement defects within the crystal lattice structure, and such defects effectively decrease the mean free path and thus shorten the recombination time. Ionizing radiation causes creation of electron-hole pair in the gate oxide and in parasitic insulating layers of the MOS devices. Calculations show increase of the dark current in depletion region caused by a single neutron. Determination of energy and angular distribution of primary knock on atoms, with 14 MeV neutron irradiation in silicon are presented.

Characterization of Diverse Gate Oxides on 4H-SiC 3D Trench-MOS Structures

2013 ◽  
Vol 740-742 ◽  
pp. 691-694 ◽  
Author(s):  
Christian T. Banzhaf ◽  
Michael Grieb ◽  
Achim Trautmann ◽  
Anton J. Bauer ◽  
Lothar Frey
Keyword(s):  
Silicon Dioxide ◽  
Dielectric Breakdown ◽  
Interface State ◽  
Oxide Semiconductor ◽  
Breakdown Field ◽  
Flat Band ◽  
Mos Devices ◽  
State Densities ◽  
Mos Structures

This study focuses on the characterization of silicon dioxide (SiO2) layers, either thermally grown or deposited on trenched 100 mm 4H-silicon carbide (SiC) wafers. We evaluate the electrical properties of silicon dioxide as a gate oxide (GOX) for 3D metal oxide semiconductor (MOS) devices, such as Trench-MOSFETs. Interface state densities (DIT) of 1*1011cm-2eV-1under flat band conditions were determined using the hi-lo CV-method [1]. Furthermore, current-electric field strength (IE) measurements have been performed and are discussed. Trench-MOS structures exhibited dielectric breakdown field strengths up to 10 MV/cm.

Effect of Phosphorus Implantation Prior to Oxidation on Electrical Properties of Thermally Grown SiO2/4H-SiC MOS Structures

2014 ◽  
Vol 806 ◽  
pp. 133-138 ◽  
Author(s):  
Aleksey Mikhaylov ◽  
Tomasz Sledziewski ◽  
Alexey Afanasyev ◽  
Victor Luchinin ◽  
Sergey A. Reshanov ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Reference Sample ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Phosphorus Concentration ◽  
Interface Traps ◽  
Mos Capacitor ◽  
Mos Devices ◽  
Dry Oxidation ◽  
Mos Structures

The electrical properties of metal-oxide-semiconductor (MOS) devices fabricated using dry oxidation on phosphorus-implanted n-type 4H-SiC (0001) epilayers have been investigated. MOS structures were compared in terms of interface traps and reliability with reference sample which was produced by dry oxidation under the same conditions. The notably lower interface traps density measured in MOS capacitor with phosphorus concentration exceeding 1018 cm-3 at the SiO2/SiC interface was attributed to interface traps passivation by incorporated phosphorus ions.

Semiconductor biosensors

1987 ◽  
Vol 316 (1176) ◽  
pp. 47-60 ◽  
Keyword(s):  
Immobilized Enzymes ◽  
Oxide Semiconductor ◽  
Gas Sensitivity ◽  
Metal Gates ◽  
Mos Devices ◽  
Steady State Responses ◽  
Catalytic Metal ◽  
Mos Structures ◽  
State Responses

Hydrogen- and ammonia-sensitive metal-oxide semiconductor (MOS) structures are described. Special attention is paid to ammonia-sensitive MOS devices with thin ( ca . 3 nm) iridium or platinum gates. It is shown how these devices can be used in combination with immobilized enzymes to develop bioprobes or biosensing systems. The temperature dependence of the gas sensitivity of MOS structures with catalytic metal gates is considered. It is demonstrated that at low temperatures (30-40 °C) iridium gates have a faster response to ammonia than platinum gates, and that Ir-Mos structures thus are better suited for the development of biosensors. It is also shown that at high temperatures (190-200 °C) platinum gates can be used to detect unsaturated hydrocarbons such as ethylene. Gas evolution from ripening fruits was monitored with such a sensor. Some biosensing applications of ammonia sensitive Ir-gate MOS devices are described; for example, the determination of urea and creatinine. The devices are used both to measure a pulse of ammonia in a flowthrough system and to measure in situ steady-state responses as a bioprobe. The special features of gas sensors used for biosensing purposes are summarized.

Charge-Transfer Dipoles at the Si-SiO2 Interface and the Metal-Semiconductor Worfunction Difference In Mos Devices.

1987 ◽  
Vol 105 ◽  
Author(s):  
Hisham Z. Massoud
Keyword(s):  
Dipole Moment ◽  
Charge Transfer ◽  
Dipole Moments ◽  
Silicon Substrates ◽  
Interface Dipole ◽  
Mos Devices ◽  
Flatband Voltage ◽  
The Difference ◽  
Definition Of ◽  
Mos Structures

AbstractThe magnitude of the dipole moment at the Si-SiO2 interface resulting from partial charge transfer that takes place upon the formation of interface bonds has been calculated. The charge transfer occurs because of the difference in electronegativity between silicon atoms and SiO2 molecules which are present across the interface. Results obtained for (100) and (111) silicon substrates indicate that the magnitude of the interface dipole moment is dependent on substrate orientation and the interface chemistry. Dipole moments at the Si-SiO2 and gate-SiO2 interfaces should be included in the definition of the flatband voltage VFB of MOS structures. CV-based measurements of the metal-semiconductor workfunction difference φms on (100) and (111) silicon oxidized in dry oxygen and metallized with Al agree with the predictions of this model. Other types of interface dipoles and their processing dependence are briefly discussed.

scholarly journals Kinetics Of Charge Generation During Formation Of Hf And Zr Silicate Dielectrics

2003 ◽  
Vol 765 ◽  
Author(s):  
Theodosia Gougousi ◽  
M. Jason Kelly ◽  
Gregory N. Parsons
Keyword(s):  
Photoelectron Spectroscopy ◽  
State Density ◽  
Fixed Charge ◽  
Charge Generation ◽  
Flatband Voltage ◽  
Partial Neutralization ◽  
High Dielectric ◽  
Charged Defects ◽  
Kinetics Of ◽  
Oxidation Mechanisms

AbstractUnderstanding charged defects in high dielectric constant insulators is a critical challenge for advanced devices. We have formed thin Zr and Hf silicates by oxidation of thin metal films sputtered on clean Si(100) and studied the effect of oxidation time (15 to 300s) and temperature (600 or 900°C) on the flatband voltage using capacitance vs. voltage measurements. We find that the thermal budget during oxidation and the type of oxidizing agent (slow vs. fast) affect the amount of fixed charge in the film significantly. Oxidation of 0.8nm of Zr metal on Si at 600°C in N2O for 15s results in EOT=1.2nm and a shift in the flatband voltage by ∼-0.2V indicating generation of positive fixed charge. Oxidation of similar films for 300s result in EOT=2.8nm and shift of the flatband voltage by ∼-0.95V. Hf films oxidized in N2O also show increased concentrations of fixed charge for longer oxidation times. By comparison, Si oxidized in the same environment does not show this extent of flatband voltage shift. A significantly reduced charge generation rate is observed for Hf oxidation under low O2 partial pressure. Extended oxidations (up to 1h) result in increased EOT and a slight decrease in the charged defect state density. Forming Gas Anneal (FGA) results in partial neutralization of the charge. FGA after the Al gate deposition also leads to significant decrease of the EOT (from 2.7 to 2.1nm) indicating significant reaction of the film with the gate metal. X-ray photoelectron spectroscopy for thin films indicates formation of Zr and Hf-silicates. However, for thick Hf films the low O2 oxidation process results in less silicon incorporation in the film as compared to films oxidized in N2O. Results suggest that understanding oxidation mechanisms will be important in isolating andcontrollingfixedchargeinhigh-kdielectrics.

scholarly journals A comparative study of hole and electron inversion layer quantization in MOS structures

2010 ◽  
Vol 7 (2) ◽  
pp. 185-193 ◽  
Author(s):  
Amit Chaudhry ◽  
Nath Roy
Keyword(s):  
Charge Density ◽  
Marked Decrease ◽  
Inversion Layer ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Gate Capacitance ◽  
Variation Approach ◽  
Inversion Charge ◽  
Mos Structures ◽  
Good Agreement

In this paper, an analytical model has been developed to study inversion layer quantization in nanoscale Metal Oxide Semiconductor Field Effect Oxide p-(MOSFET). n-MOSFETs have been studied using the variation approach and the p-MOSFETs have been studied using the triangular well approach. The inversion charge density and gate capacitance analysis for both types of transistors has been done. There is a marked decrease in the inversion charge density and the capacitance of the p-MOSFET as compared to n-MOSFETs. The results are compared with the numerical results showing good agreement.

Characterization of GaN MOS Structures Using Photoanodically Grown Oxides with Respect to FET Devices

2000 ◽  
Vol 639 ◽  
Author(s):  
D. Mistele ◽  
T. Rotter ◽  
R. Ferretti ◽  
F. Fedler ◽  
H. Klausing ◽  
...  
Keyword(s):  
Gate Dielectrics ◽  
Photoelectrochemical Cell ◽  
Oxide Growth ◽  
Metal Source ◽  
Device Applications ◽  
Small Density ◽  
Wet Chemical ◽  
Mos Structures ◽  
Strong Depletion

ABSTRACTPhotoanodically grown Ga2O3 layers were characterized with respect to their suitability as gate dielectrics for GaN based MOSFET Device applications. The Ga2O3 layers were produced in a photoelectrochemical cell using aqueous solutions of KOH. IV characterization of MOS structures show insulating behavior of the oxide layers and CV measurements indicate a small density of states at the oxide/GaN interface. Integrating the wet chemical oxide growth in a MOSFET device fabricating process includes tungsten as gate metal together with H2O2 as etching solution for the gate metal. Source/drain areas were made free of oxide by the alkaline developer of a conventional lithographic step and metallization was done by using the liftoff technique. MOS structures show no inversion mode but strong depletion in reverse biasing mode.

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