Comprehensive 2D-carrier profiling of low-doping region by high-sensitivity scanning spreading resistance microscopy (SSRM) for power device applications

L. Zhang, M. Koike, M. Ono, S. Itai, K. Matsuzawa, S. Ono, W. Saito, M. Yamaguchi, Y. Hayase, K. Hara

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Superjunction (SJ) MOSFETs with low on-resistance and high sustain voltage are widely used as main switching power devices. For the p/n-pillars of SJ-power devices, precise doping at low-doping region below 1016 cm- 3 concentrations is required, and thus high-sensitivity 2D-carrier profiling of the pillars is indispensable where conventional SCM is insufficient. Previously, we developed the high-vacuum SSRM enabling high-spatial resolution and site-specific 2D-carrier profiling. In this study, we investigated comprehensively the feasibility of applying SSRM to SJ-power devices at low doping below 1016 cm- 3, with both SJ-diodes and low-doping references. The bias dependence of SSRM was analyzed on SJ-diodes and was compared with T-CAD simulations, and both the p- and the n-pillars demonstrate Schottky-like behavior between the probe and the sample. Consequently, the pn-junction delineation also moved with applied bias. We also performed SSRM on reference-staircase structures with low-doping layers down to 1014 cm- 3 of p, n and p/n types, and comparison with SIMS and SRP confirmed the high sensitivity of SSRM. The Schottky contact of the probe-sample was found to be pronounced at low-doping region, particularly p-type doped region. Therefore, the bias polarity should be taken into account to obtain correct information at the low-doping region.

Original languageEnglish
Pages (from-to)1559-1563
Number of pages5
JournalMicroelectronics Reliability
Volume55
Issue number9-10
DOIs
Publication statusPublished - Aug 2015
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Safety, Risk, Reliability and Quality
  • Condensed Matter Physics
  • Surfaces, Coatings and Films
  • Electrical and Electronic Engineering

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