No abstract

In the present study, we have investigated the temporal evolution of 6H-SiC (0001) surface under 100keV Ar+ ion irradiation at oblique incidence (θ=60°). The topographical changes introduced by ion beam were examined using scanning force microscopy, and it is demonstrated that while at short time scales, surface morphology is dominated by dots with average diameter of 30nm, periodic height modulations or ripples emerge at the later time scales. Existing theories of ripple formation have been invoked to explain various features of the observed ripples. Ripple structures developed on a physically stable material such as SiC are expected to show very small time degradation and therefore, would be more advantageous for various technological applications as compared to those grown on conventional semiconductors such as Si, GaAs, InP, etc.

Studies on the effect of the frequency tuning on the bremsstrahlung spectra, beam intensities, and beam shape of various ions have been carried out in the 10 GHz NANOGAN ECR ion source. The warm and cold components of the electrons were found to be directly correlated with beam intensity enhancement in case of Ar(9+) but not so for O(5+). The warm electron component was, however, much smaller compared to the cold component. The effect of the fine tuning of the frequency on the bremsstrahlung spectrum, beam intensities and beam shape is presented.

The authors have developed metallic ion beams in the energy range of a few keV to a few MeV using a low-energy ion-beam facility (LEIBF) consisting of a 10GHz all-permanent-magnet electron cyclotron resonance (ECR) ion source placed on a high-voltage (200kV) platform. The metallic vapors were achieved by plasma sputtering, using a micro-oven and volatile compounds to produce multiply charged ECR plasma. The ions were then extracted from the plasma and their energy and momentum were analyzed using a high-resolution dipole magnet. Charge-state distributions (CSDs) of three metallic ECR plasmas (Cu, Ni, and Sn) produced by different techniques are presented to help in using low-energy metallic ions for implantation. We present the CSD studies of metallic ECR plasma and highlight the physics of the process involved.

X-ray bremsstrahlung measurements from the 18 GHz High Temperature Superconducting Electron Cyclotron Resonance Ion Source, Pantechnik-Delhi Ion Source were measured as a function of negative dc bias voltage, keeping all other source operating parameters fixed and the extraction voltage in the off condition. The optimization of medium and highly charged ions of argon with similar source operating parameters is described. It is observed that the high temperature component of the electron is altered significantly with the help of bias voltage, and the electron population has to be maximized for obtaining higher current.