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Tunneling in Systems of Coupled Dopant-Atoms in Silicon Nano-devices.

Moraru D, Samanta A, Tyszka K, Anh le T, Muruganathan M, Mizuno T, Jablonski R, Mizuta H, Tabe M - Nanoscale Res Lett (2015)

Bottom Line: One pathway to observe and characterize such fundamental operation is to focus on identifying isolated or coupled dopants in nanoscale silicon transistors, the building blocks of present electronics.We also discuss tunneling transport behavior based on the analysis of low-temperature I-V characteristics for devices representative for different regimes of doping concentration, i.e., different inter-dopant coupling strengths.This overview outlines the present status of the field, opening also directions toward practical implementation of dopant-atom devices.

View Article: PubMed Central - PubMed

Affiliation: Department of Electronics and Materials Science, Faculty of Engineering, Shizuoka University, Shizuoka, Japan. moraru.daniel@shizuoka.ac.jp.

ABSTRACT
Following the rapid development of the electronics industry and technology, it is expected that future electronic devices will operate based on functional units at the level of electrically active molecules or even atoms. One pathway to observe and characterize such fundamental operation is to focus on identifying isolated or coupled dopants in nanoscale silicon transistors, the building blocks of present electronics. Here, we review some of the recent progress in the research along this direction, with a focus on devices fabricated with simple and CMOS-compatible-processing technology. We present results from a scanning probe method (Kelvin probe force microscopy) which show direct observation of dopant-induced potential modulations. We also discuss tunneling transport behavior based on the analysis of low-temperature I-V characteristics for devices representative for different regimes of doping concentration, i.e., different inter-dopant coupling strengths. This overview outlines the present status of the field, opening also directions toward practical implementation of dopant-atom devices.

No MeSH data available.


Related in: MedlinePlus

Single-electron tunneling operation of single-dopant transistors at elevated temperatures. a Stub-channel SOI-FET (doped with a doping concentration ND ≈ 1 × 1018 cm−3), with a design in which P-donors can experience enhanced dielectric confinement effect. b Schematic depiction of channel potential with some P-donors having deeper ground state energy level. Such donors will be observed in tunneling transport at higher temperatures. c Temperature dependence of ID-VG characteristics (VD = 5 mV), showing a SET current peak emerging at the highest temperature of ~100 K [31]
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Fig5: Single-electron tunneling operation of single-dopant transistors at elevated temperatures. a Stub-channel SOI-FET (doped with a doping concentration ND ≈ 1 × 1018 cm−3), with a design in which P-donors can experience enhanced dielectric confinement effect. b Schematic depiction of channel potential with some P-donors having deeper ground state energy level. Such donors will be observed in tunneling transport at higher temperatures. c Temperature dependence of ID-VG characteristics (VD = 5 mV), showing a SET current peak emerging at the highest temperature of ~100 K [31]

Mentions: We implement this concept in the design of nanoscale SOI-FETs, in particular in the shape of the channel. We designed stub-shaped-channel SOI-FETs (as shown in Fig. 5a), in which sharp corners of the channel could provide favorable conditions for enhancement of dielectric confinement effect, as illustrated schematically in Fig. 5b for one P-donor. As shown in Fig. 5c, for the smallest such devices, we found that new current peaks emerge at lower VG values by increasing temperature. These newly emerging peaks were attributed to single-electron tunneling through P-donors with deeper ground states (see Fig. 5b); tunneling through such deeper-level P-donors could not be observed at lower temperatures because of the low tunneling rates. The final current peak appears at a temperature of about 100 K, which is one of the highest temperatures at which single-electron tunneling via dopant-QDs has been reported so far [31]. From the Arrhenius analysis of the barrier height, we found that the donor giving rise to this final current peak has a barrier height larger than 100 meV (> > 45 meV, ionization energy of P-donors in bulk Si) [31]. This is consistent with an enhancement of the dielectric confinement effect, suggesting a possible pathway toward achieving higher tunneling-operation temperatures for single-dopant transistors [35]. Controlling the design and pattern in such extremely small scales remains, however, significantly challenging and a serious hurdle in front of future development of this approach, but such small structures can be studied in details by first-principle simulations in order to predict useful properties [36].Fig. 5


Tunneling in Systems of Coupled Dopant-Atoms in Silicon Nano-devices.

Moraru D, Samanta A, Tyszka K, Anh le T, Muruganathan M, Mizuno T, Jablonski R, Mizuta H, Tabe M - Nanoscale Res Lett (2015)

Single-electron tunneling operation of single-dopant transistors at elevated temperatures. a Stub-channel SOI-FET (doped with a doping concentration ND ≈ 1 × 1018 cm−3), with a design in which P-donors can experience enhanced dielectric confinement effect. b Schematic depiction of channel potential with some P-donors having deeper ground state energy level. Such donors will be observed in tunneling transport at higher temperatures. c Temperature dependence of ID-VG characteristics (VD = 5 mV), showing a SET current peak emerging at the highest temperature of ~100 K [31]
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4582038&req=5

Fig5: Single-electron tunneling operation of single-dopant transistors at elevated temperatures. a Stub-channel SOI-FET (doped with a doping concentration ND ≈ 1 × 1018 cm−3), with a design in which P-donors can experience enhanced dielectric confinement effect. b Schematic depiction of channel potential with some P-donors having deeper ground state energy level. Such donors will be observed in tunneling transport at higher temperatures. c Temperature dependence of ID-VG characteristics (VD = 5 mV), showing a SET current peak emerging at the highest temperature of ~100 K [31]
Mentions: We implement this concept in the design of nanoscale SOI-FETs, in particular in the shape of the channel. We designed stub-shaped-channel SOI-FETs (as shown in Fig. 5a), in which sharp corners of the channel could provide favorable conditions for enhancement of dielectric confinement effect, as illustrated schematically in Fig. 5b for one P-donor. As shown in Fig. 5c, for the smallest such devices, we found that new current peaks emerge at lower VG values by increasing temperature. These newly emerging peaks were attributed to single-electron tunneling through P-donors with deeper ground states (see Fig. 5b); tunneling through such deeper-level P-donors could not be observed at lower temperatures because of the low tunneling rates. The final current peak appears at a temperature of about 100 K, which is one of the highest temperatures at which single-electron tunneling via dopant-QDs has been reported so far [31]. From the Arrhenius analysis of the barrier height, we found that the donor giving rise to this final current peak has a barrier height larger than 100 meV (> > 45 meV, ionization energy of P-donors in bulk Si) [31]. This is consistent with an enhancement of the dielectric confinement effect, suggesting a possible pathway toward achieving higher tunneling-operation temperatures for single-dopant transistors [35]. Controlling the design and pattern in such extremely small scales remains, however, significantly challenging and a serious hurdle in front of future development of this approach, but such small structures can be studied in details by first-principle simulations in order to predict useful properties [36].Fig. 5

Bottom Line: One pathway to observe and characterize such fundamental operation is to focus on identifying isolated or coupled dopants in nanoscale silicon transistors, the building blocks of present electronics.We also discuss tunneling transport behavior based on the analysis of low-temperature I-V characteristics for devices representative for different regimes of doping concentration, i.e., different inter-dopant coupling strengths.This overview outlines the present status of the field, opening also directions toward practical implementation of dopant-atom devices.

View Article: PubMed Central - PubMed

Affiliation: Department of Electronics and Materials Science, Faculty of Engineering, Shizuoka University, Shizuoka, Japan. moraru.daniel@shizuoka.ac.jp.

ABSTRACT
Following the rapid development of the electronics industry and technology, it is expected that future electronic devices will operate based on functional units at the level of electrically active molecules or even atoms. One pathway to observe and characterize such fundamental operation is to focus on identifying isolated or coupled dopants in nanoscale silicon transistors, the building blocks of present electronics. Here, we review some of the recent progress in the research along this direction, with a focus on devices fabricated with simple and CMOS-compatible-processing technology. We present results from a scanning probe method (Kelvin probe force microscopy) which show direct observation of dopant-induced potential modulations. We also discuss tunneling transport behavior based on the analysis of low-temperature I-V characteristics for devices representative for different regimes of doping concentration, i.e., different inter-dopant coupling strengths. This overview outlines the present status of the field, opening also directions toward practical implementation of dopant-atom devices.

No MeSH data available.


Related in: MedlinePlus