Abstract
We have experimentally investigated the hydrogen sensitivity of InP high- electron mobility transistors (HEMTs) with a WSiN-Ti-Pt-Au gate stack. We have found that exposure to hydrogen produces a shift in the threshold voltage of these devices that is one order of magnitude smaller than published data on conventional Ti-Pt-Au gate HEMTs. We have studied this markedly improved reliability through a set of quasi-two-dimensional mechanical and electrostatic simulations. These showed that there are two main causes for the improvement of the hydrogen sensitivity. First, the separation of the Ti-layer from the semiconductor by a thick WSiN layer significantly reduces the stress in the heterostructure underneath the gate. Additionally, the relatively thinner heterostructure used in this study and the presence of an InP etch-stop layer with a small piezoelectric constant underneath the gate reduces the amount of threshold voltage shift that is caused by the mechanical stress.
Original language | English |
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Pages (from-to) | 305-310 |
Number of pages | 6 |
Journal | IEEE Transactions on Electron Devices |
Volume | 52 |
Issue number | 3 |
DOIs | |
Publication status | Published - 2005 Mar |
Externally published | Yes |
Keywords
- High-electron mobility transistors (HEMTs)
- Hydrogen
- InP
- Piezoelectric effect
- Reliability
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Electrical and Electronic Engineering