The effects of nitrogen profile and concentration on negative bias temperature instability of plasma enhanced atomic layer deposition HfOxNy prepared by in situ nitridation
Abstract:Articles you may be interested inDependences of nitrogen incorporation behaviors on the crystallinity and phase distribution of atomic layer deposited Hf-silicate films with various Si concentrations J. Appl. Phys. 104, 054101 (2008) We have prepared plasma enhanced atomic layer deposition HfO x N y thin films by in situ nitridation using nitrogen/oxygen mixture plasma and studied the effects of nitrogen contents and profiles on the negative bias temperature instability ͑NBTI͒. The nitrogen depth profiles and … Show more
“…2(d), V th decreases monotonically from 4.08 to 2.85 V with increasing N 2 flow rate from 0 to 16 sccm, owing to the C ox increase and also the nitrogen-induced positive oxide charges. 22,23) The k values of the HfLaO films in Table I are smaller than many reported values because the HfLaO films in this work are not crystalline owing to their low postdeposition annealing temperature (400 °C), which is much lower than others (600-1000 °C). In addition, the oxidation of the Si substrate during the annealing and sputtering can result in a low-k interlayer at the Si=HfLaO interface, thus further decreasing the k value.…”
contrasting
confidence: 55%
“…2(c)] 17) and a large number of positive fixed oxide charges in dielectrics. 22,23) Therefore, carrier scattering could be enhanced, as revealed by the deterioration of μ sat , I on , and I on =I off for N 2 flow rates higher than 4 sccm in this work.…”
A comparative study on the electrical characteristics of amorphous InGaZnO (a-IGZO) thin-film transistors (TFTs) with HfLaO and HfLaON gate dielectrics is conducted. With the appropriate incorporation of nitrogen into the HfLaO gate dielectric, the saturation mobility of the TFTs can reach 31.3 cm2 V−1 s−1, which is more than twice that of the control sample with the HfLaO gate dielectric, as a result of the passivation of traps at/near the dielectric/a-IGZO interface by the nitrogen incorporation. However, the electrical characteristics (such as saturation mobility, on-current, and on-current/off-current ratio) of the devices tend to deteriorate with excessive nitrogen incorporation owing to nitrogen-related defects generated in the dielectric.
“…2(d), V th decreases monotonically from 4.08 to 2.85 V with increasing N 2 flow rate from 0 to 16 sccm, owing to the C ox increase and also the nitrogen-induced positive oxide charges. 22,23) The k values of the HfLaO films in Table I are smaller than many reported values because the HfLaO films in this work are not crystalline owing to their low postdeposition annealing temperature (400 °C), which is much lower than others (600-1000 °C). In addition, the oxidation of the Si substrate during the annealing and sputtering can result in a low-k interlayer at the Si=HfLaO interface, thus further decreasing the k value.…”
contrasting
confidence: 55%
“…2(c)] 17) and a large number of positive fixed oxide charges in dielectrics. 22,23) Therefore, carrier scattering could be enhanced, as revealed by the deterioration of μ sat , I on , and I on =I off for N 2 flow rates higher than 4 sccm in this work.…”
A comparative study on the electrical characteristics of amorphous InGaZnO (a-IGZO) thin-film transistors (TFTs) with HfLaO and HfLaON gate dielectrics is conducted. With the appropriate incorporation of nitrogen into the HfLaO gate dielectric, the saturation mobility of the TFTs can reach 31.3 cm2 V−1 s−1, which is more than twice that of the control sample with the HfLaO gate dielectric, as a result of the passivation of traps at/near the dielectric/a-IGZO interface by the nitrogen incorporation. However, the electrical characteristics (such as saturation mobility, on-current, and on-current/off-current ratio) of the devices tend to deteriorate with excessive nitrogen incorporation owing to nitrogen-related defects generated in the dielectric.
“…138,318 It is, for example, relatively straightforward to incorporate N atoms into oxide thin films by the addition of N 2 to a plasma generated in O 2 . 38,73,128,134,143,146,319 Such controlled doping of thin film materials is difficult to achieve with strictly thermally-driven ALD reactions.…”
Section: Increased Choice Of Precursors and Materialsmentioning
Plasma-assisted atomic layer deposition (ALD) is an energy-enhanced method for the synthesis of ultra-thin films with Å-level resolution in which a plasma is employed during one step of the cyclic deposition process. The use of plasma species as reactants allows for more freedom in processing conditions and for a wider range of material properties compared with the conventional thermally-driven ALD method. Due to the continuous miniaturization in the microelectronics industry and the increasing relevance of ultra-thin films in many other applications, the deposition method has rapidly gained popularity in recent years, as is apparent from the increased number of articles published on the topic and plasma-assisted ALD reactors installed. To address the main differences between plasma-assisted ALD and thermal ALD, some basic aspects related to processing plasmas are presented in this review article. The plasma species and their role in the surface chemistry are addressed and different equipment configurations, including radical-enhanced ALD, direct plasma ALD, and remote plasma ALD, are described. The benefits and challenges provided by the use of a plasma step are presented and it is shown that the use of a plasma leads to a wider choice in material properties, substrate temperature, choice of precursors, and processing conditions, but that the processing can also be compromised by reduced film conformality and plasma damage. Finally, several reported emerging applications of plasma-assisted ALD are reviewed. It is expected that the merits offered by plasma-assisted ALD will further increase the interest of equipment manufacturers for developing industrial-scale deposition configurations such that the method will find its use in several manufacturing applications.
“…The extraction of capacitance equivalent thickness ͑CET͒ values and interface state density ͑D it ͒ is described in our previous reports. 12,13 Figure 1͑a͒ shows XPS spectra in Al 2p binding energy region for as-deposited and HTA ͑T a = 800°C͒ HfO 2 samples with Al 2 O 3 top layer ͑Si/ HfO 2 / Al 2 O 3 ͒. For both samples, Al 2p peak is observed clearly at 75 eV, indicating the presence of Al 2 O 3 top layer.…”
Titanium oxide (TiO2) layer was used to control the flatband voltage (VFB) of p-type metal-oxide-semiconductor field effect transistors. TiO2 was deposited by plasma enhanced atomic layer deposition (PE-ALD) on hafnium oxide (HfO2) gate dielectrics. Comparative studies between TiO2 and Al2O3 as capping layer have shown that improved device properties with lower capacitance equivalent thickness (CET), interface state density (Dit), and flatband voltage (VFB) shift were achieved by PE-ALD TiO2 capping layer.
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