Impact of atomic layer deposition temperature on HfO2/InGaAs metal-oxide-semiconductor interface properties

Abstract

We have studied the impact of atomic-layer-deposition (ALD) temperature on the HfO2/InGaAs metal-oxide-semiconductor (MOS) interface with a comparison to the Al2O3/InGaAs interface. It is found that the interface properties such as the C-V characteristics and the interface trap density (Dit) and the interface structure of HfO2/InGaAs have strong dependence on the ALD temperature, while the Al2O3/InGaAs interfaces hardly depend on it. As a result, we have achieved the HfO2/InGaAs interfaces with low Dit comparable to that in the Al2O3/InGaAs interface by lowering the ALD temperature down to 200 °C or less. Also, we have found that As2O3 and Ga2O3 formed at the interface during ALD increase with a decrease in the ALD temperature. Combined with the ALD temperature dependence of the electrical characteristics, the better C-V characteristics and the lower Dit obtained at the lower ALD temperature can be explained by the As2O3 and Ga2O3 passivation of the HfO2/InGaAs interfaces, which is consistent with a reported theoretical result on the effective passivation of III-V MOS interfaces by trivalent oxides.

Diffusion of In0.53Ga0.47As elements through hafnium oxide during post deposition annealing

“…Wet chemical surface cleaning and pretreatments prior to high-k deposition, 3,4 variation in deposition temperature, 5 and most recently incorporation of III-V barrier layers 6 have all been shown to affect the electrical performance. A "selfcleaning" or "clean-up" phenomenon is believed to lead to reduction of the native oxides initially present on the III-V surfaces during ALD of high-k oxides, particularly using trimethylaluminum (TMA) or tetrakisethylmethylaminohafnium (TEMA-Hf) and water (H 2 O).…”

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

“…Due to the high dielectric constant and good thermal stability, HfO 2 has been regarded as a promising high-k gate dielectric for scaled InGaAs MOSFETs. 13,14 However, it has been reported that the HfO 2 /InGaAs interfaces have the inferior MOS interface properties to the Al 2 O 3 /InGaAs. 15 Therefore, the improvement of the HfO 2 /InGaAs interface properties is strongly needed to achieve low EOT and low gate leakage current with maintaining the excellent interface properties.…”

“…Similar self-cleaning effect phenomenon has been observed for HfO 2 /InGaAs and HfAlO/InGaAs gate stacks. 13,14 Figure 1(c) shows XPS In 3d spectra from the AlON/InGaAs interfaces deposited at various temperature. Judging from the In 3d spectra in Fig.…”

“…The amount of AsO x is higher than that of the reported Al 2 O 3 /InGaAs interfaces, indicating that As oxidation occurs during MOCVD of AlON and As oxides remain even at low temperature. 13 Figure 1(b) shows Ga 2p core level spectra from the AlON/InGaAs interface deposited at various temperatures. It is found that GaO x at the AlON/InGaAs interfaces also tends to increase with lowering the MOCVD temperature.…”

“…[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. Examples include in situ and ex situ deposition of amorphous silicon/germanium interlayers or nitridation pretreatment before high-k gate deposition.…”