Fabrication, characterisation, and integration of plasmonic materials towards next generation data storage technology at the industrial scale

Abstract

Plasmonic materials are known to be key in unlocking the nextgeneration of data storage capability, with Seagate Technology setto launch its first HAMR HDD this year, the Mozaic 3+. Nevertheless,there are still significant failure modes within the HAMR system which must beaddressed before full scale production can commence; a significant deficiency inmetrology for detecting such defects has been identified. In this work, theoptical and morphological changes of polycrystalline gold (Au) thin films andnanoparticles were characterised. Firstly, films were heated and characterisedvia ellipsometry over a temperature range of 25-400°C (in the wavelength range400-900nm). These results showed agreement with literature but provided limitedinsight into explaining the defects observed in failing HAMR HDDs. Aspecialised high resolution transmission electron microscopy (HRTEM) techniquewas also developed, allowing the complex grain structure within HAMR-criticalcomponents to be imaged. This formed the basis of an efficient electricaltesting system which could detect defects across the 100,000 test sites of an8-inch production wafer. In addition, A photolithography (PL) process wasestablished which could produce structures on the nanometre scale, enablingsingle particle optical testing. Dark field (DF) and cathodoluminescence (CL)spectroscopy demonstrated to be viable inline metrology options for plasmonicdevice fabrication.