Charge Storage and Optical Response of Hybrid Nanodots Floating Gate For Functional Memories

2009 ◽  
Vol 1208 ◽  
Author(s):  
Seiichi Miyazaki ◽  
Naoya Morisama ◽  
Sho Nakanishi ◽  
Mitsuhisa Ikeda ◽  
Katsunori Makihara
Keyword(s):  
Charge Injection ◽  
Chemical Vapor ◽  
Areal Density ◽  
Optical Response ◽  
Floating Gate ◽  
Charge Storage ◽  
Discrete Energy ◽  
Mos Capacitors ◽  
Capacitance Voltage ◽  
Si Quantum Dots

AbstractWe have proposed and fabricated a hybrid nanodots floating gate (FG), in which Si quantum dots (QDs) as charge injection/emission nodes and NiSi nanodots as charge storage nodes are stacked with an ultrathin SiO2 interlayer, to satisfy both large memory window and multivalued capability. In this study, Si-QDs with an areal density of ˜3×1011cm-2 were formed on ultrathin SiO2 layer by controlling SiH4 chemical vapor deposition (CVD) and NiSi nanodots were prepared by full-silicidation of Si-QDs promoted with remote H2-plasma exposure after Ni evaporation. From capacitance-voltage(C-V) characteristics of MOS capacitors with a NiSi nanodots/Si-QDs hybrid FG, stable storage of many charges in the deep potential well of each NiSi nanodot was confirmed. Also, by applying pulsed gate biases, stepwise charge injection to and emission from NiSi nanodots through discrete energy states in Si-QDs were demonstrated. In addition, by 1310nm (˜0.95eV) light irradiation, a distinct optical response in C-V characteristics was detected, which can be interpreted in terms of the shift of charge centroid in the hybrid FG stack due to transfer of photoexcited electrons from NiSi-nanodots to the Si-QDs.

Formation and Characterization of Hybrid Nanodots Floating Gate for Optoelectronic Application

2013 ◽  
Vol 1510 ◽  
Author(s):  
Seiichi Miyazaki
Keyword(s):  
Room Temperature ◽  
Drain Current ◽  
Electron Injection ◽  
Floating Gate ◽  
Back Side ◽  
Mos Capacitors ◽  
Optoelectronic Application ◽  
And Storage ◽  
Si Quantum Dots

ABSTRACTWe have fabricated a hybrid nanodots floating gate (FG) in which Si quantum dots (QDs) and silicide nanodots (NDs) are stacked with a very thin SiO2 interlayer in order to satisfy both multiple valued capability and charge storage capacity for a sufficient memory window and to open up novel functionality for optoelectronic application. In electron charging and discharging characteristics measured with application of pulsed gate biases to MOS capacitors with a hybrid NDs FG, stepwise changes in the rates for electron injection and emission were revealed with increasing pulse width at room temperature. Also, nMOSFETs with a hybrid NDs FG show unique hysteresis with stepwise changes in the drain current - gate voltage characteristics. The observed characteristics can be interpreted in terms that the electron injection and storage into silicide-NDs proceed through the discrete charged states of Si-QDs. For MOS capacitors with a triple-stacked hybrid NDs FG fabricated by adding another Si-QDs, by subgap light irradiation from the back side of the Si substrate, a distinct infrared optical response in C-V characteristics was detected at room temperature. The result is attributable to the shift of charge centroid in the hybrid NDs FG as a result of transfer of photoexcited electrons from silicide NDs to Si-QDs.

Memory effects in MOS capacitors with silicon rich oxide insulators

2000 ◽  
Vol 609 ◽  
Author(s):  
S. Lombardo ◽  
I. Crupi ◽  
C. Spinella ◽  
C. Bongiorno ◽  
Y. Liao ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Vapor Deposition ◽  
Polycrystalline Silicon ◽  
Memory Function ◽  
Chemical Vapor ◽  
Size Distributions ◽  
Mos Capacitors ◽  
Transmission Electron ◽  
Capacitance Voltage ◽  
And Storage

ABSTRACTTo form crystalline Si dots embedded in SiO2, we have deposited thin films of silicon rich oxide (SRO) by plasma-enhanced chemical vapor deposition of SiH4 and O2. Then the materials wereannealed in N2 ambient at temperatures between 950 and 1100 °C. Under such processing, the supersaturation of Si in the amorphous SRO film produces the formation of crystalline Si dots embedded in SiO2. The narrow dot size distributions, analyzed by transmission electron microscopy, are characterized by average grain radii and standard deviations down to about 1 nm. The memory function of such structures has been investigated in metal-oxidesemiconductor (MOS) capacitors with a SRO film sandwiched between two thin SiO2 layers as insulator and with an n+ polycrystalline silicon gate. The operations of write and storage are clearly detected by measurements of hysteresis in capacitance-voltage characteristics and they have been studied as a function of bias.

RESONANT TUNNELING AND COULOMB BLOCKADE IN A NANOCRYSTALLINE Si DOUBLE-BARRIER FLOATING-GATE STRUCTURE

2006 ◽  
Vol 05 (06) ◽  
pp. 853-858
Author(s):  
XINFAN HUANG ◽  
LIANGCAI WU ◽  
MIN DAI ◽  
LINWEI YU ◽  
WEI LI ◽  
...  
Keyword(s):  
Coulomb Blockade ◽  
Electron Tunneling ◽  
Chemical Vapor ◽  
Nanocrystalline Silicon ◽  
Floating Gate ◽  
Double Barrier ◽  
Nanoelectronic Devices ◽  
Gate Structure ◽  
Capacitance Voltage

We report the results of electron tunneling and Coulomb blockade in nanocrystalline silicon ( nc - Si ) double-barrier floating-gate structure ( SiO 2/ nc - Si/SiO 2) fabricated in situ in a plasma-enhanced chemical-vapor-deposition (PECVD) system for the nanoelectronic devices application. The quantum confinement and Coulomb blockade effect have been demonstrated in the capacitance–voltage (C–V) characteristics, in which unique peak structures differ remarkably from the normal smooth C–V curves. The experimental results have been explained by band diagram and equivalent circuits. By contrasted with silicon single electron transistor memory made by using ultra fancy nanotechnology, nc - Si -based memory can be fabricated with a minimum perturbation of conventional silicon technology and may be closest to industrial application.

Investigation of the Growth and Chemical Stability of Composite Metal Gates on Ultra-thin Gate Dielectrics

1998 ◽  
Vol 532 ◽  
Author(s):  
B. Claflin ◽  
M. Binger ◽  
G. Lucovsky ◽  
H.-Y. Yang
Keyword(s):  
Chemical Stability ◽  
Gate Dielectrics ◽  
Chemical Vapor ◽  
Mos Capacitors ◽  
Metal Gates ◽  
Bulk Film ◽  
Chemical Vapor Deposited ◽  
Capacitance Voltage ◽  
Dielectric Interfaces ◽  
On Line

ABSTRACTThe growth of reactively sputtered TiNx and WNx compound metal films on ultra-thin, remote plasma enhanced chemical vapor deposited SiO2 and SiO2/Si3N4 (ON) stack dielectrics is investigated from initial interface formation to bulk film by interrupted growth and on-line Auger electron spectroscopy (AES). Growth of both metals occurs uniformly without a seed layer on both dielectrics. The chemical stability of these metal/dielectric interfaces is studied by sequential on-line rapid thermal annealing treatments up to 850 °C and AES. TiNx reacts with SiO2 above 850 °C but the addition of a Si3N4 dielectric top-layer makes the TiNx/ON interface chemically stable at 850 °C. WNx/SiO2 and WNx/Si3N4 interfaces are both stable below 650 °C. MOS capacitors using TiNx or WNx metal gates and thermal SiO2 gate dielectrics exhibit excellent capacitance-voltage characteristics. The work function for TiNx lies near midgap in Si while for WNx it lies closer to the valence band.

Optical Response of Si-Quantum-Dots/NiSi-Nanodots Stack Hybrid Floating Gate in MOS Structures

2011 ◽  
Vol 470 ◽  
pp. 135-139 ◽  
Author(s):  
Naoya Morisawa ◽  
Mitsuhisa Ikeda ◽  
Katsunori Makihara ◽  
Seiichi Miyazaki
Keyword(s):  
Quantum Dots ◽  
Electron Tunneling ◽  
Floating Gate ◽  
Light Irradiation ◽  
Flat Band ◽  
Flat Band Voltage ◽  
Si Substrate ◽  
Mos Capacitors ◽  
Mos Structures ◽  
Si Quantum Dots

We have studied the effect of 1310 nm light irradiation on the charge distribution of a hybrid floating gate consisting of silicon quantum dots (Si-QDs) and NiSi Nanodots (NiSi-NDs) in MOS capacitors. The light irradiation resulted in reduced flat-band voltage shifts of the MOS capacitors in comparison to the shift in the dark. This result can be interpreted in terms of the shift of the charge centroid toward the gate side in the hybrid floating gate caused by the photoexcitation of electrons in NiSi-NDs and the subsequent electron tunneling to Si-QDs. The capacitance of the MOS capacitors at constant gate biases was modulated with pulsed light irradiation. When the light irradiation was turned off, capacitance recovered to its level in the dark, indicating that the photoexited charges were transferred between the Si-QDs and the NiSi-NDs without being emitted to the Si substrate and gate electrode.

Formation of Metal Silicide Nanodots on Ultrathin SiO2 for Floating Gate Application

2009 ◽  
Vol 154 ◽  
pp. 95-100 ◽  
Author(s):  
Seiichi Miyazaki ◽  
Mitsuhisa Ikeda ◽  
Katsunori Makihara ◽  
K. Shimanoe ◽  
R. Matsumoto
Keyword(s):  
Surface Potential ◽  
Room Temperature ◽  
Areal Density ◽  
Film Deposition ◽  
Floating Gate ◽  
Metal Silicide ◽  
Kelvin Probe ◽  
Measuring Surface ◽  
Surface Potential Measurements ◽  
Mis Capacitors

We demonstrated a new fabrication method of Pt- and Ni-silicide nanodots with an areal density of the order of ~1011 cm-2 on SiO2 through the process steps of ultrathin metal film deposition on pre-grown Si-QDs and subsequent remote H2 plasma treatments at room temperature. Verification of electrical separation among silicide nanodots was made by measuring surface potential changes due to electron injection and extraction using an AFM/Kelvin probe technique. Photoemission measurements confirm a deeper potential well of silicide nanodots than Si-QDs and a resultant superior charge retention was also verified by surface potential measurements after charging to and discharging. Also, the advantage in many electron storage per silicide nanodot was demonstrated in C-V characteristics of MIS capacitors with silicide nanodots FGs.

Compact Novel Floating Gate Offset Compensation Scheme with Low Sensitivity to Charge Injection, Clock Feedthrough and Leakage

2006 ◽  
Author(s):  
Annajirao Garimella ◽  
Lalitha Mohana Kalyani-Garimella ◽  
Jaime Ramirez-Angulo ◽  
Ramon G. Carvajal ◽  
Antonio J. Lopez-Martin
Keyword(s):  
Charge Injection ◽  
Floating Gate ◽  
Compensation Scheme ◽  
Clock Feedthrough ◽  
Offset Compensation ◽  
Low Sensitivity
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