Impact of cyclic plasma treatment on oxygen vacancy defects in TiN/HfZrO/SiON/Si gate stacks

Abstract

This work evaluates the defects in HfZrO as a function of Zr addition into HfO2 and when the dielectric was subjected to a slot-plane-antenna (SPA) plasma treatment in a cyclic process to form TiN/HfZrO/SiON/Si gate stacks. The defect energy levels, estimated by temperature-dependent current-voltage measurements, suggest that Zr addition in HfO2 modifies the charge state of the oxygen vacancy formation, V+. The influence of electron affinity variation of Hf and Zr ions on the charged oxygen vacancy levels seems to have contributed to the increase in defect activation energy, Ea, from 0.32 eV to 0.4 eV. The cyclic SPA plasma exposure further reduces the oxygen vacancy formation because of the film densification. When the dielectric was subjected to a constant voltage stress, the charge state oxygen vacancy formation changes to V2+ and improvement was eliminated. The trap assisted tunneling behavior, as observed by the stress induced leakage current characteristics, further supports the oxygen vacancy formation model.

Post Plasma Oxidation Processed ALD Al2O3/Hf1-xZrxO2Thin Films on Ge Substrates: Reliability

“…11 This contributes to the flat-band voltage shift towards positive direction with more Zr added to Hf 1-x Zr x O 2 (Fig. 6a).…”

“…This is because the addition of Zr in HfO 2 modifies the oxygen vacancy defect types, as discussed earlier, which can be attributed to the electron affinity difference between Hf and Zr ions in their oxides. 11,29 Furthermore, the electrons coming from SPAO plasma source enhances the bond strength of Hf 1-x Zr x O 2 . Because of low electron affinity, Zr ions get most of the benefits.…”

“…20,21 ALD processed Hf/Zr based high-k dielectrics have oxygen vacancy defects, which are introduced during the gate dielectric processing. 11 Additionally, defects can be present at interfaces between two dielectrics, in the interfacial layer, or at the interface between the high-k dielectrics and the metal gate. These defects act as electron traps and they charge and discharge during gate voltage sweep.…”

“…10 Slot-plane-antenna (SPA) plasma treatment has been shown to enhance the CVD and ALD grown oxides quality and reliability along with better interfacial layer properties when the films were exposed to SPA plasma during or after the deposition. 4,[11][12][13] The SPA process provides high density plasma (∼10 12 cm −3 ) at low electron temperature (0.7∼1.5 eV) with a wide process window (7∼1000 Pa) to enable a low damage plasma process compared to conventional inductively coupled plasma (ICP) or electron cyclotron resonance (ECR) plasma. 14 Recently, the use of slot-plane-antenna plasma oxidation (SPAO) has been studied for TiN/ZrO 2 /Al 2 O 3 /Ge MOS capacitors, where SPAO has been introduced in different stages (before Al 2 O 3 deposition, in between Al 2 O 3 and ZrO 2 deposition, and after the deposition of both Al 2 O 3 and ZrO 2 ) during the gate stack formation.…”

Further Cost Reduction of Battery Manufacturing

“…Even, 10 nm transistor technology is now at mass production [33]. Meticulous attention has been paid to defects of semiconductors and interfaces [34]. The whole IC industry is a noteworthy example of process control.…”