Do dopant diffusion and drift decide semiconductor device degradation and dimension limits?

Igor Lubomirsky, David Cahen

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


We explore chemical and physical limits to semiconductor device miniaturization. Minimal sizes for space charge-based devices can be estimated from Debye screening lengths of the materials used. Because a doped semiconductor can be viewed as a mixed electronic-ionic conductor, with the dopants as mobile ions, dopant intermixing across a p/n junction presents a chemical limit. Given a desired lifetime, simple relations can be derived between size and dopant intermixing for reverse- or forward-biased devices. Mostly, conditions for significant dopant mobility are far from those where the material is used. Thus, it is generally held that elemental and III-V-based p-n junctions are immune to this problem and persist because of kinetic stability. Indeed, we find this to be so for Si in the foreseeable future, but not for III-V- and II-VI-based ones. The limitation is more severe in structures with very thin undoped layers sandwiched between doped ones or vice versa, where even 1% intermixing can be critical. This decreases lifetime nearly 100 times. For example, for structures containing a 10 nm critical dimension, none of the components can have an average diffusion coefficient higher than 10-24 cm2/s for a 3 year lifetime. Ways to overcome or mitigate this limitation are indicated.

Original languageEnglish
Pages (from-to)559-565
Number of pages7
JournalSolid State Ionics
Publication statusPublished - Nov 2 2000

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics

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