A pulse current generator for dense plasma focus

A pulse current generator applied in a type of high-yield intense pulsed neutron source, the Dense Plasma Focus (DPF), is designed and developed in this paper. There are three key components in this generator. Each group of capacitors and switches is integrative to meet the DPF's requirements of low circuit inductance. A coaxial multi-channel switch is developed to solve the problems of the switch inductance, the jitter and the electrode erosion. A kind of sectorial plate transmission line is adopted to transfer the high pulse current from the capacitors to the DPF. The following technical parameters of the generator were achieved on dummy load: output current amplitude of ∼560 kA when primary capacitors are charged with 22 kV.

A New Delayering Application Workflow in Advanced 5nm Technology Device with Xenon Plasma Focus Ion Beam Microscopy

In semiconductor industry, planer analysis is important in many applications such as Passive Voltage Contrast (PVC) and sample preparation for nanoprobing. In order to achieve successful results on the planer surface analysis, a proper delayering technique is critical. As the thickness of metal line, via of Back-End-of Line (BEOL) and contact layer are getting thinner in advanced nodes, we observed convention hand polishing is facing major challenge in endpointing at exactly targeted layer and specific Region of Interest (ROI). In addition, Cobalt process starting from 5nm node brings additional challenges. Cobalt tends to be oxidized easily which becomes not friendly for nanoprobing. The alternative solution to produce good planar surface is to use Plasma Focus Ion Beam (PFIB) technique with patented DX gas assisted. PFIB changes the convention FA workflow and has been proven that the new workflow improves the efficiency of planar failure analysis such as PVC and nanoprobing sample preparation.

Shelf life of plasma focus chambers with deuterium-tritium filling

The paper presents the results of an experimental study of the shelf life of sealed plasma focus chambers with deuterium-tritium and deuterium fillings. Shelf life is defined as maintaining the level of neutron yield during operation of PF chambers as part of pulsed neutron generators after long storage intervals. The release of impurities from the inner surfaces of the PF chamber and the accumulation of he-lium He3 due to the decay of tritium in the volume of the sealed-off PF chambers leads to a significant decrease in the neutron radiation yield several years after the chamber is filled with the working mixture. The paper shows that the shelf life of the chambers is significantly increased when using a gas generator, in which hy-drogen isotopes are contained in a bound state, and are released into the inner volume of the chamber only for the duration of operation as part of neutron gen-erators. It has been shown experimentally that spherical chambers of the PF9 type provide a level of neutron radiation yield Y, close to the initial value in the manu-facture of chambers, after more than 10 years of storage.