Research Article Development of Simple Designs of Multitip Probe Diagnostic Systems for RF Plasma Characterization M. Y. Naz, 1,2 S. Shukrullah, 1,2 A. Ghaffar, 2,3 and N. U. Rehman 4 1 Department of Fundamental and Applied Sciences, Universiti Teknologi PETRONAS, 31750 Tronoh, Perak, Malaysia 2 Department of Physics, University of Agriculture, Faisalabad 38040, Pakistan 3 Department of Electrical Engineering, King Saud University, Riyadh 11451, Saudi Arabia 4 Department of Physics, COMSATS Institute of Information Technology, Islamabad, Pakistan Correspondence should be addressed to M. Y. Naz; yasin603@yahoo.com and S. Shukrullah; zshukrullah@gmail.com Received 22 August 2013; Accepted 4 December 2013; Published 5 February 2014 Academic Editors: L. Jing and N. Lisitza Copyright © 2014 M. Y. Naz et al. his is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Multitip probes are very useful diagnostics for analyzing and controlling the physical phenomena occurring in low temperature discharge plasmas. However, DC biased probes oten fail to perform well in processing plasmas. he objective of the work was to deduce simple designs of DC biased multitip probes for parametric study of radio frequency plasmas. For this purpose, symmetric double probe, asymmetric double probe, and symmetric triple probe diagnostic systems and their driving circuits were designed and tested in an inductively coupled plasma (ICP) generated by a 13.56 MHz radio frequency (RF) source. Using I-V characteristics of these probes, electron temperature, electron number density, and ion saturation current was measured as a function of input power and illing gas pressure. An increasing trend was noticed in electron temperature and electron number density for increasing input RF power whilst a decreasing trend was evident in these parameters when measured against illing gas pressure. In addition, the electron energy probability function (EEPF) was also studied by using an asymmetric double probe. hese studies conirmed the non-Maxwellian nature of the EEPF and the presence of two groups of the energetic electrons at low illing gas pressures. 1. Introduction he low pressure discharge plasma can be excited and sus- tained by diferent plasma sources [1–3] and ICP source is one of them [4, 5]. In ICPs, the plasma chemistry is mainly con- trolled by the gas temperature and electron energies [1, 6]. It reveals that the role of electron temperature and number den- sity is very important in order to understand the phenomena of electron impact ionization and excitation processes [7, 8]. he phenomena of low pressure plasma discharges become very complex during the conversion of electron energy into some other forms such as chemical energy, sound energy, light energy, and heat. In ICPs, the energetic electrons have frequent collisions with each other and with other plasma species and remain in an equilibrium state with a deinite electron energy distribution function (EEDF) and electron energy probability function (EEPF) [1]. For the Maxwellian energy distribution, the semilogarithmic plot of EEPF is a straight line which reveals that it is more important and simple to analyze in comparison with corresponding EEDF. In recent years, a lot of work has been done in order to fully characterize the ICPs [7] and many eforts are under way for the measurement of plasma parameters like electron number density (  ), ion number density (  ), electron temperature (  ), plasma potential (  ), electron saturation current ( eo ), ion saturation current ( io ), electron energy distribution function (EEDF), and so forth in a very precise way [8]. Diferent tools and techniques [7, 9] can be employed to characterize the discharge plasma but the electrostatic probes are considered to be the most powerful and experimentally simple technique for plasma characterization over a wide range of plasma densities because they did not require the assumption that the plasma should be in local thermody- namic equilibrium. Irvin Langmuir was the irst who mea- sured the volt-ampere characteristics by inserting a single conducting wire into plasma and then using it; he determined Hindawi Publishing Corporation e Scientific World Journal Volume 2014, Article ID 279868, 8 pages http://dx.doi.org/10.1155/2014/279868