Composition dependence of interface control and optimization on the performance of an HfTiON gate dielectric metal-oxide-semiconductor capacitor

Abstract

Composition dependence of interface control, band alignment and electrical properties of HfTiON/Si grown by sputtering has been studied by spectroscopy ellipsometry (SE), x-ray photoelectron spectroscopy (XPS) and electrical measurement. Analysis from XPS has confirmed that the interfacial layer consisting of silicate and SiO x is formed unavoidably, irrespective of composition ratio. Meanwhile, reduction in band gap and asymmetric band alignment has been detected for HfTiON films with the increase in Ti composition. To meet the requirements of high-k dielectrics with the barrier height of over 1 eV, the incorporation composition ratio needs to be carefully optimized. As a result, improved C-V characteristics and reduced leakage current have been achieved from HfTiON gate dielectric MOS capacitors with optimized composition ratio of Hf:Ti = 1:1, which can be attributed to the reduction in oxygen-related traps and the obtained near-symmetric band alignment relative to Si.

Determination of optical constant and electrical properties of sputtering-derived HfTiON gate dielectrics

“…Currently, it has been reported that nitrogen incorporation into Hf-based high k gate dielectrics, such as HfON, HfAlON and HfLaON, have been focused to meet the urgent need for advanced MOS device applications because it can effectively lessen the gate leakage current, enhance the crystallization temperature, reduce charge trapping, and further scale down the equivalent oxide thickness (EOT) [16][17][18][19]. He et al have characterized the effect of nitrogen incorporation on high-j dielectric films and observed the beneficial characteristics, including excellent resistance to interdiffusion of elements between different layers, improved thermodynamic stability and suppressed interfacial state density [20,21]. Based on previous publications it can be noted that the origination of interface defects in high-k/Si gate stack may be related to interstitial oxygen [O i ] or oxygen vacancy [V o ] defect at interface or in the oxide film [22].…”

Deposition-power-modulated optical and electrical properties of sputtering-derived HfTiOx gate dielectrics

“…6 shows the experimentally determined dielectric function ε ¼ ε 1 þiε 2 of the HfTiO x films. The dielectric dispersion (ε) of with the relevant of n and k is shown below [9,17]: . 3.…”

“…Moreover, HfeTi oxides also exhibited remarkable thermal stability [8]. Additionally, Ti and Hf are both 4-valence elements, so Ti-doped HfO 2 would not cause any increase of oxygen vacancies, resulting in avoiding the increase of leakage current in the film, which is desired in the CMOS devices [9].…”

Effect of dimethylaluminumhydride-derived aluminum oxynitride passivation layer on the interface chemistry and band alignment of HfTiO-InGaAs gate stacks

“…The increase in E v can be understood by the effect of the oxides existing at the interface between HfTiO and InGaAs, which is in good agreement with the conclusion form Robertson that the band offset of high-k oxides/high mobility substrates can be increased due to the interfacial layer. 32 Taking the measured energy-bandgap of MOCVD-derived AlON and sputtering-deposited HfTiO to be 7.20 and 4.60 eV, 18,19,33 offset ( E c ) of 1.04 eV is deduced with AlON passivation layer, whereas 0.88 eV without the passivation, as illustrated in Figs. 5(a) and 5(b).…”

“…Currently, Ti-doped Hf-based a Author to whom correspondence should be addressed. [16][17][18][19] However, direct deposition of Hfbased high-k gate dielectrics on InGaAs exhibits anomalous characteristics with larger frequency dispersion, hysteresis, and also low effective mobility, originating from the oxides-induced interface pining. 13,20 Hence, the necessity of surface passivation prior to the high-k gate dielectric deposition to minimize the oxides formation and eliminate the Fermi level pinning effect has been addressed by some researchers.…”