Academia.eduAcademia.edu

Figure 8 – uploaded by Yury Matveyev

See full PDFdownloadDownload figure
Fig. 8. Schematic of the samples for measurement of the effect of thermal treatment on the size of the dipole at the metal/insulator interface.

Figure 8 Schematic of the samples for measurement of the effect of thermal treatment on the size of the dipole at the metal/insulator interface.

Related Figures (13)

Fig. 1. Schematic diagram of the PLD-XPES-LEIS research complex based on an XSAM-800 spectrometer (Kratos)
Fig. 1. Schematic diagram of the PLD-XPES-LEIS research complex based on an XSAM-800 spectrometer (Kratos)
Fig. 2. Illustration to the model describing the kinetics of degradation of ultrathin HfO, layer on Si07(0.5 nm)/Si(100) as a result of vacuum annealing. HfO,,. As a result, in the vicinity of the formed nanopores, where the SiO, layer at t Hf starts to react with s formed at the interface. The fact that Hfsilicide silicide are is partially oriented in t he HfO./Si interface is destructed, ilicon, and the nuclei of hafnium he direction <100> of the Si sub- strate cut in the same direction (by the Rutherford back- scattering d ata) confirm ates at the interface wit! face. At the later stage, clusters of HfSi, coarsen into polycrystall s the suggestion that silicide nucle- h Si rather than on the HfO, sur- line grains of ~0.1 um in size, which are observed during the analysis by scanning tunnel micros- copy. respect to silicon. To evaluate their applicability in nanoelectronics, their thermodynamic properties, specifically, reactivity in contact with silicon should be clarified. The performed investigation of ultrathin Lu,O, and Yb,O,; layers grown on Si substrates by the ALD method showed that these rare-earth oxides are unstable in air and are converted into hydroxides (Me(OH);, Me = Lu, Yb). This reaction is reversible and proceeds in the inverse direction at JT = 300°C in vacuum. In contact with silicon, the Lu,O, and Yb,O, ultrathin layers form silicates; this reaction is also reversible and proceeds in the inverse direction at T= 950°C (Fig. 3). The obtained results agree with the thermodynamic evaluations. Specifically, if Lu,O; is in contact with SiO,, the driving force, which leads to the formation of silicate (Lu,0,+Si0O, — Lu,SiO;), appears. If we accept AH for the silicate of Lu to be the same as for those of Y and La, we obtain
Fig. 2. Illustration to the model describing the kinetics of degradation of ultrathin HfO, layer on Si07(0.5 nm)/Si(100) as a result of vacuum annealing. HfO,,. As a result, in the vicinity of the formed nanopores, where the SiO, layer at t Hf starts to react with s formed at the interface. The fact that Hfsilicide silicide are is partially oriented in t he HfO./Si interface is destructed, ilicon, and the nuclei of hafnium he direction <100> of the Si sub- strate cut in the same direction (by the Rutherford back- scattering d ata) confirm ates at the interface wit! face. At the later stage, clusters of HfSi, coarsen into polycrystall s the suggestion that silicide nucle- h Si rather than on the HfO, sur- line grains of ~0.1 um in size, which are observed during the analysis by scanning tunnel micros- copy. respect to silicon. To evaluate their applicability in nanoelectronics, their thermodynamic properties, specifically, reactivity in contact with silicon should be clarified. The performed investigation of ultrathin Lu,O, and Yb,O,; layers grown on Si substrates by the ALD method showed that these rare-earth oxides are unstable in air and are converted into hydroxides (Me(OH);, Me = Lu, Yb). This reaction is reversible and proceeds in the inverse direction at JT = 300°C in vacuum. In contact with silicon, the Lu,O, and Yb,O, ultrathin layers form silicates; this reaction is also reversible and proceeds in the inverse direction at T= 950°C (Fig. 3). The obtained results agree with the thermodynamic evaluations. Specifically, if Lu,O; is in contact with SiO,, the driving force, which leads to the formation of silicate (Lu,0,+Si0O, — Lu,SiO;), appears. If we accept AH for the silicate of Lu to be the same as for those of Y and La, we obtain
Fig. 3. Formation of lutetium oxide layers by the ALD method and their subsequent annealing. Starting surface (a) after deposi- tion and situating in atmosphere, (b) after annealing in vacuum to 300°C, and (c) after rapid annealing in Ny to T= 950°C.
Fig. 3. Formation of lutetium oxide layers by the ALD method and their subsequent annealing. Starting surface (a) after deposi- tion and situating in atmosphere, (b) after annealing in vacuum to 300°C, and (c) after rapid annealing in Ny to T= 950°C.
Fig. 4. Rutherford backscattering spectra of the LaAlO,(30 nm) thin-film sample on Si: (a) after the growth by the ALD method and (b) after RTA. Recently, based on the performed investigations, binary and ternary compounds based on La and Dy are consid- ered as undergate dielectrics of the next generation, instead of those already realized on the basis of HfO). However, their structural and dielectric properties and thermal stability (on Si), in the case of thin-film lantha- num aluminate (LaAlO,) depend on the method and parameters of the growth. The performed structural and electrical studies of initially amorphous layers (by the x- ray-diffraction data of thin-film LaAIO, layers grown by the ALD method on the Si substrate) showed that the LaAISiO,,. alumosilicate is formed (Fig. 4) [11] asa result of rapid hermal annealing (RTA) (T = 950°C, t = 60s) in contact with silicon. In this case, the band gap of the dielectric E, increases from 6.3 to 7.0 eV (Fig. 5). It should be noted that contrary to expectations, the alumosilicate permittivity also increases from € ~ 11 to 18. In this case, a substantial decrease in hysteresis and the number of sur- face states is observed; however, a positive built-in charge in he film’s bulk and an increase in the leakage currents take place. It is possible that this effect can be explained by the presence of hydroxyl groups in the starting film. In the course of annealing, hydroxyl groups are decomposed into This transformation leads to a considerable increase in permittivity. Therefore, vacuum annealing can be used as the technological procedure of increasing the permittivity of the lutetium oxide film completely or partially trans- formed into the silicate state. However, when silicate com- pletely transforms into oxide at the Lu,O,/Si interface at an elevated temperature (900°C), the process of the reduction of lutetium oxide to metal starts.
Fig. 4. Rutherford backscattering spectra of the LaAlO,(30 nm) thin-film sample on Si: (a) after the growth by the ALD method and (b) after RTA. Recently, based on the performed investigations, binary and ternary compounds based on La and Dy are consid- ered as undergate dielectrics of the next generation, instead of those already realized on the basis of HfO). However, their structural and dielectric properties and thermal stability (on Si), in the case of thin-film lantha- num aluminate (LaAlO,) depend on the method and parameters of the growth. The performed structural and electrical studies of initially amorphous layers (by the x- ray-diffraction data of thin-film LaAIO, layers grown by the ALD method on the Si substrate) showed that the LaAISiO,,. alumosilicate is formed (Fig. 4) [11] asa result of rapid hermal annealing (RTA) (T = 950°C, t = 60s) in contact with silicon. In this case, the band gap of the dielectric E, increases from 6.3 to 7.0 eV (Fig. 5). It should be noted that contrary to expectations, the alumosilicate permittivity also increases from € ~ 11 to 18. In this case, a substantial decrease in hysteresis and the number of sur- face states is observed; however, a positive built-in charge in he film’s bulk and an increase in the leakage currents take place. It is possible that this effect can be explained by the presence of hydroxyl groups in the starting film. In the course of annealing, hydroxyl groups are decomposed into This transformation leads to a considerable increase in permittivity. Therefore, vacuum annealing can be used as the technological procedure of increasing the permittivity of the lutetium oxide film completely or partially trans- formed into the silicate state. However, when silicate com- pletely transforms into oxide at the Lu,O,/Si interface at an elevated temperature (900°C), the process of the reduction of lutetium oxide to metal starts.
Fig. 5. Spectra of losses of reflected electrons for the LaAlO,(30 nm) thin-film sample on Si: (a) after the growth by the ALD method and (b) after RTA.
Fig. 5. Spectra of losses of reflected electrons for the LaAlO,(30 nm) thin-film sample on Si: (a) after the growth by the ALD method and (b) after RTA.
Fig. 6. TEM image of the transverse section of the nanodi- mensional MIS Ni/NiSi/Si/HfO,/Si structure formed by the combination of ALD and PLD methods. WF,,, where KE is the kinetic energy of a photoelectron, hv isthe energy of the photon that caused the photoelectric effect, and WF,, and WF are the work functions of the spectrometer and the sample, respectively. Upon the for- mation of the chemical compound, the value of BE is determined by both the chemical state of the sample (chemical shift) and by the location of the E, since, along with the variation in the local potential (bond ionicity), the
Fig. 6. TEM image of the transverse section of the nanodi- mensional MIS Ni/NiSi/Si/HfO,/Si structure formed by the combination of ALD and PLD methods. WF,,, where KE is the kinetic energy of a photoelectron, hv isthe energy of the photon that caused the photoelectric effect, and WF,, and WF are the work functions of the spectrometer and the sample, respectively. Upon the for- mation of the chemical compound, the value of BE is determined by both the chemical state of the sample (chemical shift) and by the location of the E, since, along with the variation in the local potential (bond ionicity), the
Evolution of the bonding energy BE for Ni2p3/) and Hf4f,. and calculated values WF, (eV) during the formation of the layers of nickel silicides in situ on HfO,/Si
Evolution of the bonding energy BE for Ni2p3/) and Hf4f,. and calculated values WF, (eV) during the formation of the layers of nickel silicides in situ on HfO,/Si
Fig. 7. Schematic of the measurement of the effective work function in MIS structures by the XPES method (see the text)
Fig. 7. Schematic of the measurement of the effective work function in MIS structures by the XPES method (see the text)
Fig. 9. Evolution of the bonding energy of the XPE lines of the dielectric La4f (solid line) and Al2p (dotted line) that reflects the change of the electric dipole at the Au/LaAlO3 interface during various treatments. dipole at the metal/insulator interface for nanodimen- Using this modified procedure, the effect of thermal treatments in different media on the size of the electric dipole at the metal/insulator interface for nanodimen- formed on the MIS structure, are presented. The obtained sional MOS structures was studied [15]. In Fig. 9, the vari- ations in the bonding energy of the skeleton levels of the components of the dielectric with respect to its surface for the Au/LaAIO, system, depending on the treatments per- formed on the MIS structure, are presented. The obtained
Fig. 9. Evolution of the bonding energy of the XPE lines of the dielectric La4f (solid line) and Al2p (dotted line) that reflects the change of the electric dipole at the Au/LaAlO3 interface during various treatments. dipole at the metal/insulator interface for nanodimen- Using this modified procedure, the effect of thermal treatments in different media on the size of the electric dipole at the metal/insulator interface for nanodimen- formed on the MIS structure, are presented. The obtained sional MOS structures was studied [15]. In Fig. 9, the vari- ations in the bonding energy of the skeleton levels of the components of the dielectric with respect to its surface for the Au/LaAIO, system, depending on the treatments per- formed on the MIS structure, are presented. The obtained
Fig. 10. Schematic of magnetron deposition in the method of doubled parallel cathodes.
Fig. 10. Schematic of magnetron deposition in the method of doubled parallel cathodes.
Fig. 11. Typical X-ray diffraction patterns of the TaN film.
Fig. 11. Typical X-ray diffraction patterns of the TaN film.
Fig. 12. Overview of the prototype of the MOS transistor based on the NaN/LaA1O3/Si functional structure (magnification x50).
Fig. 12. Overview of the prototype of the MOS transistor based on the NaN/LaA1O3/Si functional structure (magnification x50).
The performed investigations and obtained data on the structural, thermodynamic, and electrical properties of new combinations of dielectric and conducting materials in MIS structures allow us to conclude that it is possible to fabricate new functional field-effect transistors, which are the background of logical facilities in CMOS structures. The obtained results can be placed in the background of the scientific and technological groundwork for the devel- opment of production processes for the fabrication of VSLIs with a design rule of 45 nm and less. Further studies and optimization of parameters of the growth and treat- ments of ready structures, including those with the use of production equipment, for the development of prerequi- sites of their application in industry, are necessary.
The performed investigations and obtained data on the structural, thermodynamic, and electrical properties of new combinations of dielectric and conducting materials in MIS structures allow us to conclude that it is possible to fabricate new functional field-effect transistors, which are the background of logical facilities in CMOS structures. The obtained results can be placed in the background of the scientific and technological groundwork for the devel- opment of production processes for the fabrication of VSLIs with a design rule of 45 nm and less. Further studies and optimization of parameters of the growth and treat- ments of ready structures, including those with the use of production equipment, for the development of prerequi- sites of their application in industry, are necessary.
Related topics:
Thin film (Physics)(nano & Micro Electronics)
580 California St., Suite 400
San Francisco, CA, 94104
© 2025 Academia. All rights reserved