Leakage Current Characteristics of Atomic Layer Deposited Al-Doped TiO₂Thin Film for Dielectric in DRAM Capacitor

Abstract

We researched the reduction of leakage current by Al doping in TiO 2 thin film. During the TiO 2 thin film deposition process, Al 2 O 3 thin film deposition was used for Al doping. XPS analysis showed that the greater the amount of Al doping in TiO 2 thin film, the fewer oxygen vacancies were found. The n-type characteristic of TiO 2 thin films is reduced as oxygen vacancies are reduced. An anatase (211) peak was detected by GIXRD analysis, and crystallinity was reduced with greater Al doping; the full width half maximum showed the crystalline size was reduced. UV-visible analysis showed the energy bandgap increased as the crystalline size became smaller, and I-V measurements showed the current density decreased to 3 × 10 −4 A cm −2 (As-dep TiO 2 : 10 −1 A cm −2 ) with Al doping. The dielectric constant remained above 20 even when doped with Al, confirming the superior properties of Al-doping TiO 2 thin film over conventional TiO 2 thin films.

Atomic layer deposition for rutile structure TiO2 thin films using a SnO2 seed layer and low temperature heat treatment

“…Figure 3(a) and table 1 show that the Ti 4+ 2p 1/2 peak (464.3 eV) and Ti 4+ 2p 3/2 (458.5 eV) compose the main peak, the same as the Ti bond in the typical TiO 2 thin film. Furthermore aspect of spin-orbit splitting, it can be found that the difference in binding energy between the two main peaks is approximately 5.7 eV, which is similar to the previous paper [35,36]. Bezerra et al reported a similar value of Ti 4+ binding energy.…”

The effect of an annealing process on atomic layer deposited TiO2 thin films

“…Previous studies showed that TiO 2 thin films have a high leakage current with an n-type semiconductor characteristic due to the oxygen vacancy present in the TiO 2 thin films. Previous studies also demonstrated that the higher the concentration of oxygen vacancy, the higher the area of the Ti 3+ 2p1/2 peak and Ti 3+ 2p3/2 peak [19]. In this research, the relative area of the Ti 3+ 2p1/2 peak and Ti 3+ 2p3/2 peak was analyzed because the concentration of oxygen vacancy was controlled according to the annealing atmosphere.…”

“…Figure 2 shows the XPS data of deposited and annealed TiO 2 (ALD 1000 cycle, 23 nm) thin films. According to previous studies, the Ti XPS peaks in the TiO2 thin film were divided into four peaks: Ti 4+ 2p1/2 peak (464.4 eV), Ti 4+ 2p3/2 peak (458.9 eV), Ti 3+ 2p1/2 peak (463.2 eV), Ti 3+ 2p3/2 peak (458.5 eV) [19]. We can confirm that the Ti 4+ 2p1/2 peak (464.5 eV) and the Ti 4+ 2p3/2 peak (458.9 eV) form the main peak.…”

High-Performance TiO2/ZrO2/TiO2 Thin Film Capacitor by Plasma-Assisted Atomic Layer Annealing

“…The Raman spectroscopy of the upper-TiO 2 in the TZT laminate structures further shows the difference between the w/ALA and w/o ALA samples in terms of the ratio of anatase and rutile TiO 2 (Figures c, S2, S3). − The similar intensity ratio between the w/and w/o ALA samples in Z0 can be explained by the lattice matching effect between the Ru bottom electrode and rutile TiO 2 , − which is dominant in determining the phase of TiO 2 compared to that of ALA when there is no heterogeneous interface (Figure c). In contrast, when the ZrO 2 interlayers were inserted, blocking the lattice matching effect, the growth of the rutile phase in the upper-TiO 2 became unfavorable.…”