Title :
Improved Electrical Properties of ALD Hfx Zr1 − xO2 Dielectrics Deposited on Ultrathin PVD Zr Underlayer
Author :
Triyoso, Dina H. ; Hegde, Rama I. ; Jiang, Jack ; Schaeffer, James K. ; Raymond, Mark V.
Author_Institution :
Freescale Semicond. Inc., Austin
Abstract :
The impact of ultrathin metal underlayer on physical and electrical properties of Hf x Zr1- x O2(x=~0.4) after high-temperature processing was investigated. An ~5-Aring Zr, ~5-Aring Hf, ~10-Aring Hf metal layer was sputter deposited prior to Hf x Zr1- x O2 growth. Cross-sectional transmission electron microscopy and secondary ions mass spectrometry analysis confirmed no Zr or Hf silicide formation between the high-k film and Si substrate even after 1000degC processing. No significant increase in equivalent oxide thickness or gate leakage current is observed on devices with metal underlayer. Furthermore, devices with a 5-Aring-thick Zr underlayer exhibited lower threshold voltage, higher mobility, and improved charge trapping characteristics.
Keywords :
atomic layer deposition; hafnium compounds; high-k dielectric thin films; silicon; sputter deposition; substrates; transmission electron microscopy; HfZrO2; Si; atomic layer deposition; charge trapping; cross-sectional transmission electron microscopy secondary ions mass spectrometry analysis; electrical properties; gate leakage current; high-k dielectric thin film; high-temperature processing; silicon substrate; sputter deposition; ultrathin PVD underlayer; ultrathin metal underlayer; Atherosclerosis; Hafnium oxide; High-K gate dielectrics; Leakage current; MOSFETs; Mass spectroscopy; Silicon; Sociotechnical systems; Threshold voltage; Zirconium; Atomic layer deposition (ALD); charge trapping; high- $k$ dielectrics; mobility; tetragonal phase;
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/LED.2007.911979
