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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.


Donor-cluster-induced potential modulations observed by KPFM. KPFM measurement of the electronic potential map for a selectively doped high-ND SOI-FET channel (with doping profile indicated on the top panel). Doping concentration for these devices is estimated to be ND ≈ 1 × 1019 cm−3. Inside the P-doped slit, dark-contrast, deep-potential regions can be seen for VBG = −4 V (marked by a dashed circle in the left panel) but are smeared out for VBG = 0 V (right panel)
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Fig3: Donor-cluster-induced potential modulations observed by KPFM. KPFM measurement of the electronic potential map for a selectively doped high-ND SOI-FET channel (with doping profile indicated on the top panel). Doping concentration for these devices is estimated to be ND ≈ 1 × 1019 cm−3. Inside the P-doped slit, dark-contrast, deep-potential regions can be seen for VBG = −4 V (marked by a dashed circle in the left panel) but are smeared out for VBG = 0 V (right panel)

Mentions: For this type of devices, as shown in Fig. 3, we can observe the potential landscape in correlation with regions defined as source, drain, and P-doped slit, identified based on correlation with the doping profile (indicated in the upper panel). The KPFM measurements shown here were taken at room temperature (T = 300 K). It can be seen from Fig. 3 that the heavily-doped (ND ≈ 1 × 1019 cm−3) region (slit) has a lower electronic potential than the nominally non-doped regions. Furthermore, as marked in the lower zoom-in panel for negative VBG, it is possible to identify fine modulations of the potential inside the heavily-doped slit. These features can be ascribed to “clusters” of several P-donors grouped together inside the selectively-doped region, according to our detailed analysis correlated with dopant-induced potential simulations [25]. It is found that such clusters (containing even more than 10 P-donors) can work as dominant QDs in the tunneling transport characteristics, with a significant effect of the selective-doping technique in controlling the QD position within the channel [26]. As VBG is made more positive, free carriers start to screen the potential and the contrast becomes significantly reduced. Thus, KPFM could also provide information about the distribution and properties of dopant-induced QDs in this more complex regime in which a number of P-donors strongly interact with each other. This regime is of particular interest for applications that aim at utilizing the molecular behavior of such multiple P-donor “clusters” in Si nanostructures.Fig. 3


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)

Donor-cluster-induced potential modulations observed by KPFM. KPFM measurement of the electronic potential map for a selectively doped high-ND SOI-FET channel (with doping profile indicated on the top panel). Doping concentration for these devices is estimated to be ND ≈ 1 × 1019 cm−3. Inside the P-doped slit, dark-contrast, deep-potential regions can be seen for VBG = −4 V (marked by a dashed circle in the left panel) but are smeared out for VBG = 0 V (right panel)
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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

Fig3: Donor-cluster-induced potential modulations observed by KPFM. KPFM measurement of the electronic potential map for a selectively doped high-ND SOI-FET channel (with doping profile indicated on the top panel). Doping concentration for these devices is estimated to be ND ≈ 1 × 1019 cm−3. Inside the P-doped slit, dark-contrast, deep-potential regions can be seen for VBG = −4 V (marked by a dashed circle in the left panel) but are smeared out for VBG = 0 V (right panel)
Mentions: For this type of devices, as shown in Fig. 3, we can observe the potential landscape in correlation with regions defined as source, drain, and P-doped slit, identified based on correlation with the doping profile (indicated in the upper panel). The KPFM measurements shown here were taken at room temperature (T = 300 K). It can be seen from Fig. 3 that the heavily-doped (ND ≈ 1 × 1019 cm−3) region (slit) has a lower electronic potential than the nominally non-doped regions. Furthermore, as marked in the lower zoom-in panel for negative VBG, it is possible to identify fine modulations of the potential inside the heavily-doped slit. These features can be ascribed to “clusters” of several P-donors grouped together inside the selectively-doped region, according to our detailed analysis correlated with dopant-induced potential simulations [25]. It is found that such clusters (containing even more than 10 P-donors) can work as dominant QDs in the tunneling transport characteristics, with a significant effect of the selective-doping technique in controlling the QD position within the channel [26]. As VBG is made more positive, free carriers start to screen the potential and the contrast becomes significantly reduced. Thus, KPFM could also provide information about the distribution and properties of dopant-induced QDs in this more complex regime in which a number of P-donors strongly interact with each other. This regime is of particular interest for applications that aim at utilizing the molecular behavior of such multiple P-donor “clusters” in Si nanostructures.Fig. 3

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.