A comparison of electrical and physical properties of MOCVD hafnium silicate thin films deposited using various silicon precursors

P. Jamison, M. Copel, M. Chudzik, M. M. Frank, B. P. Linder, R. Jammy, Wenjuan Zhu

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

We report on the impact of silicon precursor choice on the electrical and physical properties of hafnium silicate (HfSiO) gate dielectrics deposited by metalorganic chemical vapor deposition (MOCVD). Hafnium tert-butoxide (HTB) was used as the hafnium source and silane and tetraethylorthosilicate (TEOS) were used as silicon sources. Elemental depth profiles were measured with sub-nm resolution using medium energy ion scattering (MEIS). For Hf-rich films employing TEOS as the silicon precursor, relatively little Si is incorporated at the bottom interface compared with the top; while using SiH4, a more uniform Si distribution is achieved. These physical differences are then correlated with the electrical performance of transistors employing polysilicon gate electrodes. Transistors incorporating SiH4 based HfSiO x gate dielectrics with low silicon concentrations have lower C-V hysteresis and higher high field mobility than those using TEOS based dielectrics, We demonstrate polysilicon gated transistors which have an electrical thickness in inversion (Tinv) that can be scaled to ∼21 A with good leakage reduction when employing nitrided bottom interface layers in combination with optimized HfSiOx dielectrics. Reduced silicon concentration resulted in a lower inversion thickness for a fixed physical thickness contributing to the higher drive currents in transistors.

Original languageEnglish (US)
Title of host publicationGate Stack Scaling
Subtitle of host publicationMaterials Selection, Role of Interfaces, and Reliability Implications
Pages95-99
Number of pages5
Volume917
StatePublished - 2006
Externally publishedYes
Event2006 MRS Spring Meeting - San Francisco, CA, United States
Duration: Apr 17 2006Apr 21 2006

Other

Other2006 MRS Spring Meeting
CountryUnited States
CitySan Francisco, CA
Period4/17/064/21/06

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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