Generation of microdischarges in diamond substrates

We report the generation of microdischarges in devices composed of microcrystalline diamond. Discharges were generated in device structures with microhollow cathode discharge geometries. One structure consisted of an insulating diamond wafer coated with boron-doped diamond layers on both sides. A second structure consisted of an insulating diamond wafer coated with metal layers on both sides. In each case, a single sub-millimetre hole was machined through the conductor–insulator–conductor structure. The discharges were generated in a helium atmosphere. Breakdown voltages were around 500 V and discharge currents in the range 0.1–2.5 mA were maintained by a sustaining dc voltage of 300 V

Plasma enhanced atomic layer etching of high-k layers on WS₂

The etching of HfO2 and ZrO2 high-k dielectrics is studied using plasma-enhanced atomic layer etching. The etching method relies on a continuous argon inductively coupled plasma discharge, in which reactive gases are pulsed, followed by substrate biasing; both steps are separated by purge periods. It is found that pure BCl3 is too chemically active while a Cl2- BCl3 allows a high process synergy; in addition the latter gives a high selectivity to SiO2. The optimal etch conditions are applied to high-k layers deposited on top of WS2 transition metal dichalcogenide. Post-etch analysis show negligible tungsten and sulfur depletion, as well as negligible change in optical (Raman) response of the 2D layer, indicating that atomic layer etching concepts allows to prevent WS2 material loss or damage