Ultrathin decoupled plasma nitridation SiON gate dielectrics prepared with various rf powers

Abstract

Decoupled plasma nitridation (DPN) SiON films for short channel complementary metal-oxide-semiconductor (CMOS) devices were prepared with various rf powers. As we increased the SiON deposition power from 200to400W, it was found that gate leakage current increased while gate breakdown voltage decreased. It was also found that the authors can achieve more uniform thickness and nitrogen distributions across the wafers, smaller off-state current, and better Vt rolloff characteristics from the PMOS field-effect transistors (MOSFETs) with 400W DPN SiON films. Furthermore, it was found that they can achieve larger hot carrier injection (HCI) lifetime and better HCI resistance from the NMOSFETs with 400W SiON films. However, it was also found that negative bias temperature instability lifetime of the PMOSFETs with 200W SiON films was longer.

Electrical and structural properties of ultrathin SiON films on Si prepared by plasma nitridation

“…2,3,6 Additionally, an enhanced defect density has been observed in the case of N pileup at the Si/ SiO 2 interface. 4,6,8 The value of the density of interface states ͑D it ͒ for thin oxynitride films typically increases with nitrogen concentration. 6 A typical value of D it for oxynitrides without postnitridation annealing and for a N concentration of around 5% is D it ϳ 10 11 cm −2 , 6,9,10 while values as high as 10 13 cm −2 were also measured.…”

Comparative Investigation of Flat-Band Voltage Modulation by Nitrogen Plasma Treatment for Advanced HKMG Technology

“…As the physical gate length of RMG scaling down to below 14nm for sub-7nm technology node, the gap filling volume becomes rigorous and the V T tuning capability by this method turns inadequate for CMOS IC applications. 8 To realize a large V T adjustment range with a more simplified stack structure and film thickness control process as well as no degradation in mobility and reliability of devices, a series of novel methods have been proposed, including decoupled plasma nitridation, 9,10 impurity doped high-k dielectric, 11,12 SiH 4 -soak of barrier layer, 13 ion implantation in work function metal, 14,15 and high-k capping layer with dipole. 16 Among these new technologies, the approach of nitrogen plasma treatment on the multi-layer high-k/metal-gate (HKMG) stack demonstrates a simplified process cost and a strong modulation ability; several initial experimental results and hypothetical predictions are published.…”