Clustering Kinetics of Arsenic and Phosphorus in Laser Annealed Silicon

1985 ◽  
Vol 45 ◽  
Author(s):  
Josef Goetzlich
Keyword(s):  
Laser Annealing ◽  
Most Probable Number ◽  
High Dose ◽  
Second Phase ◽  
Probable Number ◽  
Relaxation Phase ◽  
Post Annealing ◽  
Residual Damage ◽  
Heavily Doped ◽  
Kinetics Of

ABSTRACTHigh-dose arsenic and phosphorus ion implanted silicon was annealed either by a CW CO2 or a pulsed Nd:YAG laser creating supersaturated dopant concentrations up to 3·1021 cm−3. The relaxation of these metastable electrically active atoms was investigated during thermal post-annealing at temperatures between 600 and 1000°C for times between 3 and 106 s. In heavily doped samples which contain residual damage after laser annealing, a very fast first relaxation phase is observed followed by a much slower second phase. In samples without residual damage only this second slower phase is seen. Carrier concentration profile measurements show that the saturation concentration after the relaxation depends only on temperature and corresponds to the concentration in thermal equilibrium. Using reaction kinetics a cluster model is proposed which demonstrates that in As doped layers the most probable number of As atoms in one cluster depends on temperature (4 As atoms at 700°C, 3 As atoms at 800 - 1000°C). In P doped layers the most probable clusters contain 3 P atoms at temperatures between 700 and 900°C.

Infrared Optical Properties of Ion Implanted and Laser Annealed Silicon

1980 ◽  
Vol 1 ◽  
Author(s):  
Masanobu Miyao ◽  
Teruaki Motooka ◽  
Nobuyoshi Natsuaki ◽  
Takashi Tokuyama
Keyword(s):  
Optical Properties ◽  
Carrier Concentration ◽  
Laser Annealing ◽  
Electronic States ◽  
Free Carrier ◽  
High Dose ◽  
Carrier Relaxation ◽  
Carrier Effective Mass ◽  
Heavily Doped ◽  
Infrared Optical Properties

ABSTRACTElectronic states of extremely heavily doped n-type Si obtained by high dose ion implantation and laser annealing are investigated by measuring the infrared optical properties. Free carrier effective mass (m*) and carrier relaxation time (τ) are obtained as a function of carrier concentration (1019−5×1021 cm−3). Values of m* and τ increase and decrease, respectively, with the increase of carrier concentration. These results are discussed in relation to the occupation of electrons in a new valley of the conduction band.

Analysis of Defects in Laser Annealed GaAs

1980 ◽  
Vol 2 ◽  
Author(s):  
John Fletcher ◽  
J. Narayan ◽  
D. H. Lowndes
Keyword(s):  
Laser Annealing ◽  
Laser Energy ◽  
Threshold Energy ◽  
High Dose ◽  
Surface Degradation ◽  
Plan View ◽  
Implantation Damage ◽  
Transmission Electron ◽  
Residual Damage ◽  
Good Agreement

ABSTRACTThe nature and depth distributions of residual damage in ion implanted and pulsed ruby laser annealed GaAs have been studied using both plan-view and cross-section transmission electron microscopy (TEM) specimens for high dose (1.0 × 1015 cm−2) Zn+, Se+ and Mg+ implants. It was found that laser energy densities above 0.36 J/cm2 were required to remove the implantation damage, this threshold energy density giving good agreement with that indicated by electrical activation measurements. Laser induced surface degradation of the GaAs was present even for energy densities as low as 0.25 J/cm2, and more severe damage, with the introduction of dislocations near the surface, was present for energy densities above 0.8 J/cm2. The use of thin SiO2 layers for encapsulation during laser annealing was found to substantially reduce this surface degradation.

Ion Implantation in Gallium Indium Arsenide

1983 ◽  
Vol 27 ◽  
Author(s):  
M. Anjum ◽  
M. A. Shahid ◽  
S. S. Gill ◽  
B. J. Sealy ◽  
J. H. Marsh
Keyword(s):  
Ion Implantation ◽  
Indium Arsenide ◽  
Room Temperature ◽  
Gallium Indium Arsenide ◽  
High Dose ◽  
Long Time ◽  
Residual Damage ◽  
Heavily Doped

ABSTRACTWe have studied the formation of heavily doped n-type layers in LPE GaInAs using ion implantation. 400 keV selenium ions have been implanted in dose ranges of 5 × 1013 to 1 × 1015 cm−2 at room temperature. For the high dose implants we have reproducibly achieved activities of 20–40% and sheet Hall mobilities of 700–1000 cm−2 V−1 s−1 and peak carrier concentrations of about 1019 cm−3. TEM and RBS results indicate that for long time anneals residual damage persists in the implanted layers, however, anneals at 800°C for 30 seconds perfectly recrystallize the implanted layers.

Analysis of Coliform and Colifecal Total Pollution Test on Various Types of Drinking Water Using the MPN (Most Probable Number) Method

2020 ◽  
Vol 2 (2) ◽  
Author(s):  
Wanda Aulya ◽  
Fadhliani Fadhliani ◽  
Vivi Mardina
Keyword(s):  
Drinking Water ◽  
Fecal Coliform ◽  
Pathogenic Bacteria ◽  
Microbiological Quality ◽  
Coliform Bacteria ◽  
Most Probable Number ◽  
Inspection Method ◽  
Sample Number ◽  
Probable Number ◽  
Fecal Coliform Bacteria

Water is the main source for life and also the most severe substance caused by pollution. The mandatory parameters for determining microbiological quality of drinking water are total non-fecal Coliform bacteria and Coliform fecal (Escherichia coli). Coliform bacteria are a group of microorganisms commonly used as indicators, where these bacteria can be a signal to determine whether a water source has been contaminated by bacteria or not, while fecal Coliform bacteria are indicator bacteria polluting pathogenic bacteria originating from human feces and warm-blooded animals (mammals) . The water inspection method in this study uses the MPN (Most Probable Number) method which consists of 3 tests, namely, the presumption test, the affirmation test, and the reinforcement test. The results showed that of 15 drinking water samples 8 samples were tested positive for Coliform bacteria with the highest total bacterial value of sample number 1, 15 (210/100 ml), while 7 other samples were negative. From 8 positive Coliform samples only 1 sample was stated to be negative fecal Coliform bacteria and 7 other samples were positive for Coliform fecal bacteria with the highest total bacterial value of sample number 1 (210/100 ml).

Cemaran Eshericia coli dalam makanan laut yang beredar di pasar tradisional Kota Pontian

2015 ◽  
Vol 1 (1) ◽  
pp. 44
Author(s):  
Rafika Sari ◽  
Pratiwi Apridamayanti
Keyword(s):  
Most Probable Number ◽  
Probable Number

Latar Belakang: Makanan laut merupakan salah satu jenis makanan yang banyak dikonsumsi oleh masyarakat selain sebagai komoditi ekspor. Mengkonsumsi makanan laut yang telah terkontaminasi bakteri hidup atau toksin yang dihasilkannya dapat menyebabkan keracunan makanan. Tujuan penelitian ini adalah untuk mengetahui adanya kontaminasi bakteri koliform E.coli sebagai indikator pencemaran pada makanan laut dan memberikan informasi kelayakan dan keamanan konsumsi dari makanan laut di dua pasar tradisional terbesar di daerah Pontianak. Metode: Sampel yang digunakan adalah ikan, sotong dan udang. Penelitian terhadap sampel dilakukan menggunakan uji Most Probable Number (MPN) yang dilengkapi dengan uji biokimia untuk mengidentifikasi jenis bakteri pada sampel melalui penanaman bakteri pada media agar Lactose Broth (LB) dan Briliant Green Lactose Bile Broth (BGLB). Hasil: Hasil penelitian menunjukkan bakteri koliform E.coli terdeteksi pada 100% sampel dengan nilai MPN yang tidak memenuhi kriteria kelayakan konsumsi, yakni >3/g. Kesimpulan: Makanan yang ada tidak memenuhi kriteria kelayakan konsumsi.

The Occurrence of Legionella Bacteria in Cooling Towers in South Africa

1991 ◽  
Vol 24 (2) ◽  
pp. 149-152 ◽  
Author(s):  
N. A. Grabow ◽  
E. J. Pienaar ◽  
R. Kfir
Keyword(s):  
South Africa ◽  
Most Probable Number ◽  
Cooling Towers ◽  
Probable Number ◽  
Service Water ◽  
Standard Plate ◽  
Viable Bacteria ◽  
Plate Counts ◽  
High Level ◽  
Biocide Treatment

A total of 510 service water samples from cooling towers throughout South Africa were analysed for the presence of Legionella bacteria. Legionella was detected using an immuno-labelling technique based on the most probable number principle. Only cultural (viable) bacteria were counted. Legionellae were found in most of the samples tested. However, in only 4% of the samples a high level of legionellae was recorded. No correlation was found between the numbers of legionellae and those of standard plate counts. Biocide treatment was shown to be effective in the removal of the bacteria from cooling towers after a 3-month treatment period.

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