Mechanisms of temperature dependence of threshold voltage in high-k/metal gate transistors with different TiN thicknesses |
| |
Authors: | Yukio Nishida Shin Yokoyama |
| |
Affiliation: | 1. Graduate School of Advanced Sciences of Matter, Hiroshima University, Hiroshima 739-8530, Japan;2. Research Institute for Nanodevice and Bio Systems, Hiroshima University, Hiroshima 739-8527, Japan |
| |
Abstract: | The change in temperature coefficient of the threshold voltage (=dVth/dT) for poly-Si/TiN/high-k gate insulator metal–oxide–semiconductor field-effect transistors (MOSFETs) was systematically investigated with respect to various TiN thicknesses for both n- and p-channel MOSFETs. With increasing TiN thickness, dVth/dT shifts towards negative values for both n- and p-MOSFETs. A mechanism that changes dVth/dT, depending on TiN thickness is proposed. The main origins are the work function of TiN (ΦTiN) and its temperature coefficient (dΦTiN/dT). These are revealed to change when decreasing the thickness of the TiN layer, because the crystallinity of the TiN layer is degraded for thinner films, which was confirmed by ultraviolet photoelectron spectroscopy (UPS), transmission electron microscopy (TEM) and X-ray diffraction (XRD). |
| |
Keywords: | silicon MOSFET metal gate titanium nitride threshold voltage work function temperature coefficient crystallinity |
|
|