Abstract
We have investigated the hydrogen sensitivity of InP HEMTs with a gate stack containing a thick Ti-layer (order of 1000 Å). We have found that the hydrogen-induced piezoelectric effect in these devices is an order of magnitude smaller than conventional Ti/Pt/Au-gate HEMTs with a thin Ti layer (order of 250 Å). This markedly improved reliability can be explained through the diffusion mechanism of H in Ti which limits hydrogenation of the Ti layer to a thin sheet at the top. Using Auger Electron Spectroscopy, we have confirmed that under the studied conditions, TiHx is only formed in the top 250 Å of the Ti-layer. In some devices located in the periphery of the wafer, we have observed a second hydrogen degradation mechanism that induces a large positive ΔVT. This appears to be related to an improperly fabricated gate recess. The use of a thick Ti layer in the gate stack allows for a simple and effective mitigation of the H-induced piezoelectric effect in InP and other III-V HEMTs.
| Original language | English |
|---|---|
| Pages (from-to) | 223-226 |
| Number of pages | 4 |
| Journal | Conference Proceedings - International Conference on Indium Phosphide and Related Materials |
| Publication status | Published - 2003 Jul 28 |
| Externally published | Yes |
| Event | 2003 International Conference Indium Phosphide and Related Materials - Santa Barbara, CA, United States Duration: 2003 May 12 → 2003 May 16 |
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Electrical and Electronic Engineering