Recent results in ion beam induced charge microscopy: Unconnected junction contrast and an assessment of single contact IBIC

Abstract

The recent development of Ion Beam Induced Charge Microscopy (IBIC) promises to deliver a powerful imaging tool for the analysis of active regions in microelectronics devices. The high penetration power (47 μm for 2 MeV protons in Si) allows direct high resolution access to buried structures, a feature not available to the well established EBIC (Electron Beam Induced Current) technique. As multi-level designs become more prevalent this deep penetration is a significant advantage. We report several results: firstly, that contrast is present in IBIC images from junctions that are not directly connected to the preamplifier. The contrast from unconnected junctions vanishes if these junctions are short circuited. Secondly, we discuss the degradation of IBIC images under prolonged irradiation for protons and He+ ions. Finally, we discuss the feasibility of single connection IBIC imaging. We demonstrate that IBIC imaging is possible with only one connection to the device substrate. © 1997 Elsevier Science B.V.