Titanium Hydride Formation in Ti/Pt Films: the Impact on Ti/Pt/Au-gated III-V FETs.
Abstract
Ti/Pt metal layers are an integral part of the gate stack of many III-V field-effect transistors (FETs). These devices are known to be affected by H(sub 2) exposure. In this study, Auger Electron Spectroscopy (AES) measurements of Ti/Pt bilayers are correlated with electrical measurements of InAlAs/InGaAs/InP FETs fabricated with Ti/Pt/Au gates. The PET measurements show that H(sub 2) exposure shifts the device threshold voltage through the piezoelectric effect. AES reveals the formation of titanium hydride (TiH(sub x)) in Ti/Pt bilayers after identical H(sub 2) exposures. These results indicate that the volume expansion associated with TiH(sub x) formation causes compressive stress in Ti/Pt/Au gates, leading to the piezoelectric effect. After a I subsequent recovery anneal in N(sub 2), the FET measurements show that V(sub T) recovers. AES measurements confirm that the TiH(sub x) in hydrogenated Ti/Pt bilayers also decreases after further annealing in N(sub 2).
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 22, 1999
- Accession Number
- ADA366046
Entities
People
- J. A. Del Alamo
- R. R. Blanchard
Organizations
- Massachusetts Institute of Technology