Electrical and Reliability Characteristics of MOS Devices With Ultrathin $\hbox{SiO}_{2}$ Grown in Nitric Acid Solutions
TL;DR: In this article, the electrical and reliability properties of ultrathin silicon dioxide, grown by immersing silicon in nitric acid solution have been studied, and it is observed that the temperature, oxidation time, and concentration of the nitric acids solution play important roles in determining the thickness as well as the quality of the oxide.
Abstract: In this paper, electrical and reliability properties of ultrathin silicon dioxide, grown by immersing silicon in nitric acid solution have been studied. It is observed that the temperature, oxidation time, and concentration of the nitric acid solution play important roles in determining the thickness as well as the quality of the oxide. Prolonged exposure to nitric acid degrades the quality of the oxide. However, it was found necessary to reduce the oxidation temperature and the concentration of nitric acid to grow oxide of thickness 2 nm. In these conditions, the leakage current and fixed oxide charge in the chemical oxide were found to be too high. However, when this chemical oxidation was followed by anodic oxidation using ac bias, the electrical and reliability characteristics of metal-oxide-semiconductor (MOS) devices showed tremendous improvement. A MOSFETs with gate oxide grown by this technique have demonstrated low subthreshold slope, high transconductance and channel mobility. It is thus proposed that chemical oxidation followed by ac anodization can be a viable alternative low-temperature technique to grow thin oxides for MOS application.
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TL;DR: In this paper, a dielectric stack with Al2O3/HfO2/SiO2 (18 nm/16 nm/25 nm) trilayer structure prepared by low temperature in situ natural oxidation during dc sputtering is investigated.
Abstract: In this work, a dielectric stack with Al2O3/HfO2/SiO2 (18 nm/16 nm/25 nm) trilayer structure prepared by low temperature in situ natural oxidation during dc sputtering is investigated We study the electrical characteristics, including the dielectric leakage of 10−8 A/cm2 at Vg=−2 V, the current transport mechanism and trap distributions through the trilayer dielectric stack The Fowler–Nordheim barrier height of the prepared Al2O3 (ϕFN,Al2O3) was extracted as 306±015 eV The current variation ratios [ΔJg/Jg(0)] during constant voltage stressing were found to decrease with raising gate stress voltages for the trilayer stack in comparison with that [ΔJg/Jg(0)] increase with raising gate stress voltages for the two-layer HfO2/SiO2 stack Shallow traps located in HfO2 were supposed to be major trapping centers within the trilayer stack The proposed method of in situ oxidation during dc sputtering is of merit and low in process temperature The trilayer dielectric stacks are an alternative option for no
22 citations
19 Dec 2012
TL;DR: Semiconductor-based ultraviolet photodiodes have been continuously developed that can be widely used in various commercial, civilian areas, and military applications, such as optical communications, missile launching detection, flame detection, UV radiation calibra- tion and monitoring, chemical and biological analysis, optical communications and astro- nomical studies, etc as mentioned in this paper.
Abstract: Semiconductor-based ultraviolet (UV) photodiodes have been continuously developed that can be widely used in various commercial, civilian areas, and military applications, such as optical communications, missile launching detection, flame detection, UV radiation calibra‐ tion and monitoring, chemical and biological analysis, optical communications, and astro‐ nomical studies, etc. [1-2]. All these applications require very sensitive devices with high responsivity, fast response time, and good signal-to-noise ratio is common desirable charac‐ teristics. Currently, light detection in the UV spectral range still uses Si-based optical photo‐ diodes. Due to the Si-based photodiodes are sensitive to visible and infrared radiation, the responsivity in the UV region is still low [3-5]. To avoid these disadvantages, wide-bandgap materials (such as diamond, SiC, III-nitrides and wide-bandgap II–VI materials) are under intensive studies to improve the responsivity and stability of UV photodiodes, because of their intrinsic visible-blindness [6].
10 citations
Cites methods from "Electrical and Reliability Characte..."
...Several fabrication methods have been employed for the formed of ultrathin SiO2 films, such as rapid thermal oxidation (RTO) [36], oxidation with excited molecules and ions [37,38], plasma oxidation [39,40], photo-oxidation [34,41], ozone oxidation [43], metal-promot‐ ed oxidation [44], anodic oxidation [45,46] and nitric acid (HNO3) vapor oxidation [47,48] etc....
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TL;DR: In this article, a tilted-substrate sputtering technique, which provides various film thicknesses in one processing step, was proposed and useful for the characterization of charge distribution in low-temperature dielectric stacks with anodic oxide interfacial layer (ANO-IL).
Abstract: Hafnium oxide dielectric stacks with anodic oxide interfacial layer (ANO-IL) were investigated under low-temperature consideration. A tilted-substrate sputtering technique, which provides various film thicknesses in one processing step, was proposed and useful for the characterization of charge distribution. It was found that charges existed in the HfO2/ANO-IL were smaller than that in HfO2/rapid-thermal-oxidation IL. The prepared samples exhibit good electrical characteristics, including small electrical hysteresis (< 10 mV), low leakage current, high effective dielectric breakdown field of 12.7 MV/cm, and maximum operating voltages of -2.74 V at 25degC and -2.32 V at 125degC for EOT = 2.3 nm stacks under a ten-year lifetime evaluation. The results suggest that the quality of IL in the dielectric stack is a critical reliability issue and that ANO is provided as a candidate for IL consideration of low-temperature dielectric stacks.
9 citations
Cites methods from "Electrical and Reliability Characte..."
...Room-temperature oxidation methods such as anodization or chemical oxidation provided other promising choices for the preparation of low-temperature IL [11], [12]....
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TL;DR: In this article, the oxide layer on the surface of a p-type silicon substrate was grown under various growth times and temperatures while under nitric acid treatment, and an efficiency improvement of absolute 2% was obtained using their laboratory fabrication process.
Abstract: In this study, we investigate the effect of nitric acid oxidation on p-type silicon solar cells. The oxide layer on the surface of a p-type silicon substrate was grown under various growth times and temperatures while under nitric acid treatment. After 30 min of growth at 23 °C, an efficiency improvement of absolute 2% was obtained using our laboratory fabrication process.
9 citations
Dissertation•
01 Jan 2010
8 citations
Cites background from "Electrical and Reliability Characte..."
...It is however possible to chemically grow thin films of SiO2 by exposing the clean silicon to nitric acid (HNO3) [152-153]....
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...Studies on SiO2 films grown via the nitric acid solution method have previously shown that interface trapped charge density is comparable to thermally grown oxide and is likely to be in the range of approximately 10 11 cm -2 , which is an order of magnitude lower than the levels of trapped charge that are necessary here [152]....
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References
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TL;DR: In this article, the effect of selective anodisation under ac bias on ultrathin (1.5-2.75-nm) silicon dioxide grown at two different temperatures, viz. 700 and 800°C, has been studied.
Abstract: In this paper the effect of selective anodisation under ac bias on ultrathin (1.5–2.75 nm) silicon dioxide grown at two different temperatures, viz. 700 °C and 800 °C have been studied. It is shown that ac anodisation is much more effective in improving the electrical properties of the ultrathin oxide compared to selective anodisation carried out under dc condition. Unlike dc anodisation, which only repairs the pinholes but does not improve the interfacial properties, ac anodisation is found to reduce the density of interface states. The parameters during ac anodisation, e.g. signal frequency and dc offset are found to have a major role in the degree of the improvement and have been optimised carefully. Best results have been obtained when ac anodisation has been carried out using a 260 mV peak-to-peak signal of frequency 5 kHz and dc offset of 70 mV.
7 citations
"Electrical and Reliability Characte..." refers background in this paper
...These parameters have been optimized previously [19]....
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...voltages, the electrical and reliability characteristics of MOS devices improve significantly [19]....
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TL;DR: In this article, the DAC-ANO oxides with thickness smaller than 3 nm were prepared by anodic oxidation (anodization) in deionized water under direct-current biasing superimposed with alternating-current signal.
Abstract: Ultra-thin gate oxides with thickness smaller than 3 nm were prepared by anodic oxidation (anodization) in deionized water under direct-current biasing superimposed with alternating-current signal (DAC-ANO). It is experimentally observed that the DAC-ANO oxides after suitable high temperature annealing have better electrical characteristics than conventional rapid thermal oxides (RTO). Other advantages of DAC-ANO oxides include lower leakage current, higher time-zero dielectric breakdown and time-dependent dielectric breakdown endurance, and less stress-induced leakage current. The charge trapping behavior under high field stress is less significant in DAC-ANO oxides than in RTO ones. The improved reliability of DAC-ANO oxides can be explained by the nature of AC switching effect. DAC-ANO oxide is a potential candidate in the application of ultra-thin gate oxide to deep sub-micron devices.
6 citations
"Electrical and Reliability Characte..." refers methods in this paper
...These new techniques include anodic oxidation [3]–[5], laser induced...
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TL;DR: In this article, a novel technique for the growth of ultrathin SiO2 at room temperature using a pulsed laser has been demonstrated, and the results show that this technique can be used to grow high quality ultra-thin siO2 films with excellent control suitable for ULSI MOSFETs.
Abstract: A novel technique for the growth of ultrathin SiO2 at room temperature using a pulsed laser has been demonstrated. It is observed that, after an initial high growth rate, the oxide thickness reduces with time and the quality of the oxide improves. The results of our experiments show that this technique can be used to grow high quality ultrathin SiO2 films with excellent control suitable for ULSI MOSFETs.
5 citations
TL;DR: In this article, the effect of selective anodisation under ac bias on ultrathin (2.75 nm) silicon dioxide grown at 800°C was studied and it was shown that ac anodization is more effective in improving the electrical properties of the ultrathsin oxide compared to selective anodicisation carried out under dc condition.
Abstract: In this paper we have studied the effect of selective anodisation under ac bias on ultrathin (2–2.75 nm) silicon dioxide grown at 800°C. It is shown that ac anodisation is more effective in improving the electrical properties of the ultrathin oxide compared to selective anodisation carried out under dc condition. Unlike dc anodisation, which only repairs the pinholes but does not improve the interfacial properties, ac anodisation is found to reduce the density of interface states. The efficacy of ac anodisation is found to depend on the ac signal frequency and best results have been obtained at a frequency of 5 kHz.
1 citations
"Electrical and Reliability Characte..." refers background in this paper
...oxidation [6]–[8], and chemical oxidation [9]–[16]....
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...910442 dielectric layers for MOS device applications [3]–[16]....
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