We have fabricated 2D and 3D structured organosilcates from epoxy functionalized polyhedral oligomeric silsesquioxanes (POSS) cage materials using holographic lithography, which can be conveniently converted to silica structures by thermal removal of the organic moieties.
The chaotic behaviours of the Rydberg hydrogen atom near a metal surface are presented. A numerical comparison of Poincaré surfaces of section with recurrence spectra for a few selected scaled energies indicates the correspondence between classical motion and quantum properties of an excited electron. Both results demonstrate that the scaled energy dominates sensitively the dynamical properties of system. There exists a critical scaled energy εc, for ε < εc, the system is near-integrable, and as the decrease of ε the spectrum is gradually rendered regular and finally turns into a pure Coulomb field situation. On the contrary, if ε > εc, with the increase of ε, the system tends to be non-integrable, the ergodic motion in phase space presages that chaotic motion appears, and more and more electrons are adsorbed on the metal surface, thus the spectrum becomes gradually simple.
Using an emissive probe technique in 'saturated floating-potential' mode, an investigation of temporal evolution of plasma potential (V p) in a large-area pulsed dual-frequency (2 MHz/13.56 MHz) inductively coupled plasma (p-DF-CCP) is carried out. The discharge is sustained by an external type ICP antenna at a pressure of 10 mTorr in argon gas environment. The 2 MHz rf is pulsed at a frequency of 1 kHz and a duty ratio of 50%. The emissive probe is located at the centre of the substrate and 20 mm above (r = 00 mm and z = −20 mm) it. The low-frequency power (P 2 MHz) is varied from 100 to 800 W, whereas the high-frequency power (P 13.56 MHz) from 100 to 700 W. V p remains positive during the whole pulse period. The prominent features in the V p profile remain similar under all operating conditions; however, the magnitude of V p depends on the applied rf powers. For further investigation, three distinct regions in a typical V p profile are clearly identified as 'overshoot-immediately after pulse begins', the 'on-time' and the 'off-time'. V p increases with increasing P 13.56 MHz and has reverse trend with P 2 MHz. The electron temperature (T e) is calculated using the relation between floating potential (V f) and plasma potential (V p) for the argon plasma and it is found that T e increases with increasing P 13.56 MHz and decreases with P 2 MHz. It is found that V p could be modulated using a suitable power combination on two frequencies (P 13.56 MHz /P 2 MHz). This paper is an attempt to investigate the time-resolved V p and T e with rf powers in a pulsed dual-frequency ICP.
To control the plasma characteristics more efficiently, a dual antenna inductively coupled plasma (DF-ICP) source composed of a 12-turn inner antenna operated at 2 MHz and a 3-turn outer antenna at 13.56 MHz was pulsed. The effects of pulsing to each antenna on the change of plasma characteristics and SiO 2 etch characteristics using Ar/C 4 F 8 gas mixtures were investigated. When the duty percentage was decreased from continuous wave (CW) mode to 30% for the inner or outer ICP antenna, decrease of the average electron temperature was observed for the pulsing of each antenna. Increase of the CF 2 /F ratio was also observed with decreasing duty percentage of each antenna, indicating decreased dissociation of the C 4 F 8 gas due to the decreased average electron temperature. When SiO 2 etching was investigated as a function of pulse duty percentage, increase of the etch selectivity of SiO 2 over amorphous carbon layer (ACL) was observed while decreasing the SiO 2 etch rate. The increase of etch selectivity was related to the change of gas dissociation characteristics, as observed by the decrease of average electron temperature and consequent increase of the CF 2 /F ratio. The decrease of the SiO 2 etch rate could be compensated for by using the rf power compensated mode, that is, by maintaining the same time-average rf power during pulsing, instead of using the conventional pulsing mode. Through use of the power compensated mode, increased etch selectivity of SiO 2 /ACL similar to the conventional pulsing mode could be observed without significant decrease of the SiO 2 etch rate. Finally, by using the rf power compensated mode while pulsing rf powers to both antennas, the plasma uniformity over the 300 mm diameter substrate could be improved from 7% for the CW conditions to about around 3.3% with the duty percentage of 30%.
Controlling time averaged ion energy distribution (IED) is becoming increasingly important in many plasma material processing applications for plasma etching and deposition. The present study reports the evolution of ion energy distributions with radio frequency (RF) powers in a pulsed dual frequency inductively discharge and also investigates the effect of duty ratio. The discharge has been sustained using two radio frequency, low (P 2 MHz ¼ 2 MHz) and high (P 13.56 MHz ¼ 13.56 MHz) at a pressure of 10 mTorr in argon (90%) and CF 4 (10%) environment. The low frequency RF powers have been varied from 100 to 600 W, whereas the high frequency powers from 200 to 1200 W. Typically, IEDs show bimodal structure and energy width (energy separation between the high and low energy peaks) increases with increasing P 13.56 MHz ; however, it shows opposite trends with P 2 MHz. It has been observed that IEDs bimodal structure tends to mono-modal structure and energy peaks shift towards low energy side as duty ratio increases, keeping pulse power owing to mode transition (capacitive to inductive) constant. V
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