Dr. Alok Ranjan

Dr. Alok Ranjan is currently a postdoctoral research fellow at Engineering Product Development (EPD) pillar at Singapore University of Technology and Design (SUTD). Alok’s current research interest includes development of physical and failure analysis techniques for emerging nanoscale devices. Alok has obtained his PhD in the field of nanoscale reliability of gate dielectrics under Prof. Pey Kin Leong (SUTD) and Dr. Sean O’Shea (IMRE, A*STAR). During his PhD, Alok has been extensively applying the scanning probe microscopy techniques under UHV for the isolation of individual defects and its electrical characterization using random telegraph noise spectroscopy techniques. Alok has published more than 20 technical papers (journals and conference proceedings) and a book chapter, including 5+ technical papers presented as a lead author at International Reliability Physics Symposium (IRPS) – being one of the top tier conferences in the field. Alok also sits on the reviewer panel for various journals including Applied Physics Letters, Scientific Reports, ACS Applied Materials and Interfaces, Microelectronics Reliability and conferences including International Symposium on the Physical and Failure Analysis of Integrated Circuits (IPFA). Alok has also won numerous awards including academic gold medal (Bachelors) and graduate research competition awards from applied materials.

Invited Talk Topic: Advances in Applications of Conduction AFM Techniques for Gate Oxide Reliability Analysis at Nanoscale

Conduction AFM (CAFM) is used to measure localized electrical properties of a surface or nanoscale device. What is less appreciated is the interplay between the electrical and mechanical behavior. I will present few examples involving friction and adhesion from our work studying the dielectric breakdown of ultrathin films in ultra-high vacuum. In the first case, I will describe an experimental approach to quantify thermal drift in nanoscale conduction measurements and also discuss an approach to prolong the dwell time of the CAFM tip at a location needed for time dependent spectroscopy. In the second case, I will describe a new method that correlates changes in the adhesion and the electrical stress induced defects in dielectric thin films. Taking a simple case of SiO2, we demonstrate that adhesion at the CAFM tip-oxide contact increases after electrical stress primarily due to interplay between chemical / ionic bonding as well as electrostatic interactions between stress induced defects and the CAFM tip. This new approach has potential to infer the trapped charge densities at the nanometer length scales in dielectrics.