Abstract
Ruthenium thin films were grown by thermal and plasma-enhanced atomic layer deposition (PE-ALD) using O2 and ammonia (NH3) plasma, respectively. RuCp2 and Ru(EtCp)2 were used as Ru precursors. Pure and low resistivity (<20 μΩ cm) Ru films were grown by PE-ALD as well as thermal ALD. PE-ALD Ru showed no nucleation delay on various substrates including TaNx, Si, and SiO2, in contrast to thermal ALD Ru. And the root-mean-square (RMS) roughness of PE-ALD Ru was lower than that of thermal ALD Ru. Additionally, metal-oxide-semiconductor (MOS) capacitor composed of p-Si/ALD Ta2O5/ALD Ru (35 nm) was fabricated and C-V measurements were performed for as-deposited sample. Very small hysteresis of 20 mV was obtained, and effective work function difference to Si substrate was minimal as -0.03 V. For comparison, MOS capacitor was fabricated using sputtered Ru and large hysteresis of 0.5 V and flat band voltage (VFB) shift to negative value were observed. This result indicates that ALD process produces more reliable, damage free Ru gate compared to sputtering process.
| Original language | English |
|---|---|
| Pages (from-to) | 39-44 |
| Number of pages | 6 |
| Journal | Microelectronic Engineering |
| Volume | 85 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 2008 Jan |
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics
- Condensed Matter Physics
- Surfaces, Coatings and Films
- Electrical and Electronic Engineering