Uniform Ultra-Thin Oxides Grown by Rapid Thermal Oxidation of Silicon in N2O Ambient

1997 ◽  
Vol 470 ◽  
Author(s):  
G. C. Xing ◽  
D. Lopes ◽  
G. E. Miner

ABSTRACTIn this paper, we report the study of rapid thermal oxidation of silicon in N2O ambient using the Applied Materials RTP Centura rapid thermal processor, and N2O oxide thickness and compositional uniformities with respect to gas flow rate and wafer rotation speed as well as other process parameters. It was found that N2O oxide uniformity is strongly dependent on gas flow rate and wafer rotation speed in addition to process pressure. With optimized setting of the process parameters, excellent oxidation uniformities (one sigma < 1%) were obtained at atmospheric pressure N2O ambient. Nitrogen concentrations of such uniform oxides grown at 1050°C atmospheric pressure N2O oxidation processes were 1.7% for a 40Å oxide and 2.5% for a 60Å oxide, respectively, as characterized by SIMS analysis.

Author(s):  
Christopher Julian Mahandran ◽  
Abdul Yasser Abd Fatah ◽  
Nurul Aini Bani ◽  
Hazilah Mad Kaidi ◽  
Mohd Nabil Bin Muhtazaruddin ◽  
...  

Thermal oxidation is a process done to grow a layer of oxide on the surface of a silicon wafer at elevated temperatures to form silicon dioxide. Usually, it en- counters instability in oxide growth and results in variation in the oxide thickness formed.  This leads to downtime of furnace and wafer scrap.  This study focuses on the factors leading to this phenomenon and finding the optimum settings of these factors. The factors that cause instability to oxide thickness were narrowed down to location of wafer in furnace, oxidation time, gas flow rate and temperature. Characterization and optimization were done using Design of Experiments. Full factorial design was implemented using 4 factors and 2 levels, resulting in 16 runs. Data analysis was done using Multiple Regression Analysis in JMP software. Actual versus predicted plot is examined to determine whether the model fit is significant. Adjusted <em>R</em><sup>2</sup> value was obtained at 99.8% or 0.998 indicating that there is very minimal variation of the data not explained by the model and thus confirming that the model is good. From the effect test, the factors were narrowed down from 4 factors to 3 factors. Location factor was found to have no impact. Significant factors that have impact are gas flow rate, oxidation time and temperature. Analyzing the leverage plots and least square mean plots, temperature was found to have the highest impact on oxide thickness. The model was further analyzed using prediction profiler in JMP to find the optimum settings for thermal oxidation process to meet the target oxide thickness of 8000A. Optimum setting for temperature was found to be at 958 C, gas flow rate at low flow rate (H<sub>2</sub>:6.5 slm and O<sub>2</sub>:4.5 slm), oxidation time at 280 min and location of wafers at both zone 1 and zone 2.


2011 ◽  
Vol 239-242 ◽  
pp. 1573-1576 ◽  
Author(s):  
Lei Zhang ◽  
Xuan Pu Dong ◽  
Wen Jun Wang ◽  
Rong Ma ◽  
Ke Li ◽  
...  

A rotating gas bubble stirring technique with specially designed equipment has been developed for the production of light alloy semi-solid slurry. The equipment was specially designed to have temperature, rotation speed and gas flow rate control functions. An Al-Si aluminum alloy was applied as the experimental material. The results showed that large volume of semi-solid slurry could be achieved with the actual stirring temperature of 4 °C to 20 °C below the liquidus temperature of the alloy, and the rotation speed of 195 r/min, and the gas flow rate of 2 L/min. A strong convection and weak stirring effect which was induced by the rotating gas bubbles in the melt was founded responsible for the formation of the semi-solid slurry.


2015 ◽  
Vol 3 (15) ◽  
pp. 3530-3535 ◽  
Author(s):  
Jing Li ◽  
Xuan-Yun Wang ◽  
Xing-Rui Liu ◽  
Zhi Jin ◽  
Dong Wang ◽  
...  

By mildly oxidizing Cu foil and slowing down the gas flow rate, centimeter-sized single-crystalline graphene was grown on Cu at atmospheric pressure.


Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1443 ◽  
Author(s):  
Maroš Vyskoč ◽  
Miroslav Sahul ◽  
Mária Dománková ◽  
Peter Jurči ◽  
Martin Sahul ◽  
...  

In this article, the effect of process parameters on the microstructure and mechanical properties of AW5083 aluminum alloy weld joints welded by a disk laser were studied. Butt welds were produced using 5087 (AlMg4.5MnZr) filler wire, with a diameter of 1.2 mm, and were protected from the ambient atmosphere by a mixture of argon and 30 vol.% of helium (Aluline He30). The widest weld joint (4.69 mm) and the highest tensile strength (309 MPa) were observed when a 30 L/min shielding gas flow rate was used. Conversely, the narrowest weld joint (4.15 mm) and the lowest tensile strength (160 MPa) were found when no shielding gas was used. The lowest average microhardness (55.4 HV0.1) was recorded when a 30 L/min shielding gas flow rate was used. The highest average microhardness (63.9 HV0.1) was observed when no shielding gas was used. In addition to the intermetallic compounds, β-Al3Mg2 and γ-Al12Mg17, in the inter-dendritic areas of the fusion zone (FZ), Al49Mg32, which has an irregular shape, was recorded. The application of the filler wire, which contains zirconium, resulted in grain refinement in the fusion zone. The protected weld joint was characterized by a ductile fracture in the base material (BM). A brittle fracture of the unshielded weld joint was caused by the presence of Al2O3 particles. The research results show that we achieved the optimal welding parameters, because no cracks and pores were present in the shielded weld metal (WM).


2018 ◽  
Vol 9 (1) ◽  
pp. 9-16
Author(s):  
S. A. Rizvi

This research article is focusing on the optimization of different welding process parameters which affect the weldability of stainless steel (AISI) 304H, Taguchi technique was used to optimize the welding parameters and the fracture mode characterization was studied. A number of experiments have been conducted. L9 orthogonal array (OA) (3×3) was applied. Analysis of variance ( ANOVA) and signal to noise ratio (SNR) was applied to determine the effect of different welding parameters such as welding current, wire feed speed and gas flow rate on mechanical, microstructure properties of SS304H. Ultimate tensile strength (UTS), toughness, microhardness (VHN), and mode of fracture was examined to determine weldability of AISI 304H and it was observed from results that welding voltage has major impact whereas gas flow rate has minor impact on ultimate tensile strength of the welded joints. Optimum process parameters were found to be 23 V, 350 IPM travel speed of wire and 15 l/min gas flow rate for tensile strength and mode of fracture was ductile fracture for tensile test specimen.


2013 ◽  
Vol 19 (6) ◽  
pp. 452-462 ◽  
Author(s):  
Mehmet Ermurat ◽  
Mehmet Ali Arslan ◽  
Fehmi Erzincanli ◽  
Ibrahim Uzman

Purpose – This paper aims to investigate the effect of four important process parameters (i.e. laser focal distance, travel speed, feeding gas flow rate and standoff distance) on the size of single clad geometry created by coaxial nozzle-based powder deposition by high power laser. Design/methodology/approach – Design of experiments (DOE) and statistical analysis methods were both used to find optimum parameter combinations to get minimum sized clad, i.e. clad width and clad height. Factorial experiment arrays were used to design parameter combinations for creating experimental runs. Taguchi optimization methodology was used to find out optimum parameter levels to get minimum sized clad geometry. Response surface method was used to investigate the nonlinearity among parameters and variance analysis was used to assess the effectiveness level of each problem parameters. Findings – The overall results show that wisely selected four problem parameters have the most prominent effects on the final clad geometry. Generally, minimum clad size was achieved at higher levels of gas flow rate, travel speed and standoff distance and at minimum spot size level of the laser focal distance. Originality/value – This study presents considerable contributions in assessing the importance level of problems parameters on the optimum single clad geometry created laser-assisted direct metal part fabrication method. This procedure is somewhat complicated in understanding the effects of the selected problem parameters on the outcome. Therefore, DOE methodologies are utilized so that this operation can be better modeled/understood and automated for real life applications. The study also gives future direction for research based on the presented results.


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