Editing Plasma Physics Laboratory (section)

=Research Machines=
==Plasma Sputter-Type Negative Ion Source (PSTNIS)==

A sequence of accelerators and focusing techniques are employed in the extraction of gas/metal ions produced in a sputter-type ion source. Enhancement of ion yield is tried with noble gases as well as with cesium vapors. The extracted and highly focused beam is studied in terms of its transport properties specifically on techniques of increasing acceleration voltage reaching to several keV. The ion current is expected to increase with increasing acceleration voltage. Acceleration voltages in the order of a few keV and a few hundred nanoamperes of ion current are essential in ion beam implantation and etching applications. Ion beam etching is necessary in the preparation of materials for various investigations such as thinning of samples for transmission electron microscopy or for texturing surfaces in the semiconductor industry. High-energy particles (ions or neutral particles) bombard the specimen in the physical process. Ion beam etching has merits over conventional metallographic etching methods specially when etching composite materials or material compounds. The production of highly energetic ions in this study is the first step towards comprehensive etching tests and parameter studies to be done on various materials. 

Group Leaders:
*Giovanni Malapit, PhD Physics student
*Christian Lorenz Mahinay, PhD Physics student

==Sheet Plasma Negative Ion Source (SPNIS)==

The sheet plasma negative ion source (SPNIS) was also designed by Dr. Henry J. Ramos. It is the first plasma facility in the Philippines.

The original SPNIS chamber was made of borosilicate glass until it was upgraded into an all-stainless steel chamber for easier operation and safety. In this manner, the plasma can be operated at higher currents without danger of implosion as would be feared if the chamber was made of glass. In the production region, thermionic electrons are produced by passing current through tungsten filaments. The gas molecules (such as hydrogen, nitrogen, and argon), that are injected into the chamber through the gas inlet port, are ionized due to collision with the thermionic electrons. A large diameter plasma is produced in a dc discharge between the cathode and anode through the two intermediate electrodes. In the extraction region, the usually cylindrical plasma is converted to a sheet configuration using a pair of samarium-cobalt (Sm-Co) permanent magnets with the north poles facing each other. This wide area plasma is focused on a hearth near the anode for application in coating of large area. A titanium disk target is placed at the anode and is sputtered by the plasma for purposes of deposition. There is a port for langmuir probe and a space for the mass analyzer for plasma characterization. In between the two regions are the plasma limiters that provide the magnetic field in the constriction. A coreless electromagnet is enclosed inside the first plasma limiter, while a ferrite magnet is located inside the second plasma limiter.

Preliminary studies on deposition of different cermet on various substrates such as aluminum, stainless steel and copper has been done on this machine. Among the deposited layers are Sn-Bi, TiCN, TiCuN, TiAlN, and TiN.

Group Leaders:
*Michelle Marie S. Villamayor, 	PhD Physics student
*Marcedon Fernandez , PhD Physics student

==Plasma Enhanced Chemical Vapor Deposition (PECVD)==

The chemical vapor deposition (CVD) technique is the most popular tool in the deposition of metastable film phase of carbon. A wide variation of this process is now in use. Plasma-enhanced chemical vapor deposition (PECVD) and hot-filament chemical vapor deposition (HFCVD) are among the widely used techniques. The interest in these techniques is due to the potential usefulness in producing diamond films suitable for semiconductor, coatings and other applications. In our previous studies, we have developed a facility which demonstrated both techniques for the synthesis of diamond and diamond-like-carbon (DLC) films. In this project, the locally fabricated facility will be upgraded for the preparation of deposition of diamond and DLC thin films intended for industrial applications. The conditions for deposition using the industrial prototype will be determined. For example, the effects of gas mixture, substrate bias and temperature on the type of film produced will be investigated. Standard surface characterization techniques such as scanning electron microscopy (SEM) , Raman spectroscopy and Fourier transform infrared spectroscopy will be used to confirm the deposits.

The PECVD facility, which is upgraded for better cooling and deposition, is made up mainly of stainless steel. Aluminum electrodes serve as the cathode and anode. Molybdenum cup serves as substrate holder and is placed between the electrodes. Plasma diagnostic is done during deposition with the Langmuir probe. The viewport that is attached in the chamber is also used for spectroscopy and to view the deposition process inside. Thermocouple and ionization gauge are used to observe the substrate temperature and vacuum pressure respectively. The PECVD evolve in a dc discharge plasma process.

Group Leader:
*Karel Pabelina, PhD Physics student

==Gas Discharge Ion Source (GDIS)==

A Gas Discharge Ion Beam Source (GDIS) is developed as an example of a low energy ion beam source. Ion beam diagnostics like beam emittance measurement and mass analysis are done to investigate optimum parameters in producing mixed species hydrogen positive ions. By producing a low energy ion beam (H+ and H2+), this source is tested for surface modification applications such as ion beam irradiation on sample polymers. The effects on structural organic polymers such as wood, polytetrafluoroethylene, polyethylene, cellulose materials and others are tried. The ion treatment that the sample surfaces undergo changes their physicochemical properties. The modification is of great significance in the moisture absorption of the material improving its characteristic features like dyeability, anti stain, and other physical characteristics. Present results can be extended to applications on other polymers, bio-organisms and semiconductors. Other gas ions like oxygen, helium and nitrogen are to be irradiated on similar polymers.

Group Leaders:
*Hernando Siy Salapare, III, PhD Physics student

==Atmospheric Microwave Plasma Jet==

The plasma jet facility is completely donated by IBF Electronic GmbH & Co. KG. The atmospheric microwave plasma jet operates at 2.45 GHz up to an input power of around 3 kW and gas flow rates of more than 1 lpm. The ignited atmospheric plasmas are contained in a cylindrical dielectric tube with a diameter upto 2 cm. Microwave energy is concentrated in the middle of the dielectric tube with the aid of a tapered waveguide. Plasma filaments and plasma flume have been oberseved at different discharge conditions. The plasma jet facility aims to make plasma processing of industrial materials more easier and faster to implement due to vacuum-free operations. It has been already demonstrated that stainless steel becomes superhydrophilic with plasma jet treatment of just a few seconds.

Group Leaders:
*Dr. Roy B. Tumlos, PhD
*Leo Mendel Rosario, PhD Physics student
*Henry V. Lee, Jr., PhD Physics student
*Julie Anne S. Ting , PhD Physics student

==Electron Cyclotron Resonance Plasma Device (ECR)==

Characterizations of a 2.45 GHz/1.5 kW magnetron from a domestic microwave oven were done. Electron temperature (2-3.8 eV) and electron density (109 ?1010 cm-3) measurements of an argon microwave discharge indicate flexibility and plasma uniformity even at millitorr pressures by removing the hexapoles or varying their distances. The source makes a resonant surface with its repulsive double hexapole. magnetic configuration. Magnetic field maps and power delivery for varying hexapole distances are obtained.

Group Leaders:
*Dr. Roy B. Tumlos, PhD
*Leo Mendel Rosario, PhD Physics student
*Henry V. Lee, Jr., PhD Physics student
*Julie Anne S. Ting , PhD Materials Science Engineering student

==Streaming Neutral Gas Ion Source (SNGI)==

The system is operated in its arc mode to produce the swan peaks of C2 in a mixed discharge of argon, helium and methane. The conditions in the optimum production of C2 will be determined as it is vital in the synthesis of carbon nanotubes.

Group Leaders:
*Aleo Paolo Pacho, PhD Physics student
*Emil Pares, MS Materials Science Engineering student

==Atmospheric Microwave Plasma Pencil==

The plasma pencil facility was produced through collaborations with IBF Electronic GmbH & Co. KG. The atmospheric microwave plasma pencil operates at 2.45 GHz with a minimum input power of 50 W and gas flow rates of more than 1 lpm. Microwave energy is transported through a coaxial rod and plasma is ignited at its pointed tip. The plasma flames of mixtures of argon with oxygen, nitrogen, or air have a diameter of up to 5 mm and lengths of around 1-2 cm. The lowest temperature attained with the center of the flame is around 60 <sup>o</sup>C. The plasma pencil is aimed for surface treatments related with biomedical applications. It has already been demonstrated that bond paper becomes superhydrophilic within just a few seconds of treatment of the plasma pencil.

Group Leaders:
*Dr. Roy B. Tumlos, PhD
*Leo Mendel Rosario, PhD Physics student
*Henry V. Lee, Jr., PhD Physics student
*Julie Anne S. Ting , PhD Materials Science Engineering student