Infrared spectroscopy of high k thin layer by multiple internal reflection and attenuated total reflection

Abstract

A complete analysis of HfO 2 high k thin layers deposited by metal organic chemical vapour deposition (MOCVD) is made by infrared spectroscopy using different optical configurations. Multiple internal reflection (MIR) and attenuated total reflection (ATR) are used, giving information about morphology and composition of the layers. Samples under investigation are HfO 2 layer of 3 to 12 nm thick deposited at 400 and 550°C on thin silicon oxide. MIR technique elucidates carbon content in the layer and ATR informs about the interface evolution, and the crystalline character of the HfO 2 layer. The high sensitivity of MIR coupled with the large spectral range available of ATR allow the full characterisation of these layers.

Growth by Liquid‐Injection MOCVD and Properties of HfO2 Films for Microelectronic Applications

“…The crystalline films exhibit the characteristic doublet for the monoclinic structure, with peaks centered around 690 cm -1 and 770 cm -1 . These positions are in good agreement with those reported by Rochat et al [18] for HfO 2 films grown by the same technique (with tetra(diethylamino)hafnium as precursor). The peak located at 770 cm -1 is specific to the monoclinic structure as it disappears when the orthorhombic or other metastable structures are stabilized.…”

Coupling of Advanced Optical and Chemical Characterization Techniques for Optimization of High-κ Dielectrics with Nanometer Range Thickness

“…1 (a) splits into two separate ones after the NH3 anneal. These peaks are attributed to a change of the crystalline state [8], starting from an amorphous state after deposition and crystallizing with the high temperature anneal under NH3. Finally the spectra of Hf-rich alloys also show an emerging peak around 1100 cm"^ attributed to the Si-N bond indicating that nitrogen is presumably not incorporated into these alloys but is directly bonded to the silicon.…”

Study of interfacial reactions and phase stabilization of mixed Sc, Dy, Hf high-k oxides by attenuated total reflectance infrared spectroscopy

“…Theory predicts this doublet to be situated at 780/694 cm À1 and 683/634 cm À1 [4], and it has been ascribed experimentally to peaks at 760 cm À1 [7] or 752 and 635 cm À1 [16,22,23]. Based on the presence of this vibration around 780 cm À1 in the spectra of HfO 2 films of all thicknesses studied, it can be concluded that all of these films contain monoclinic HfO 2 .…”

“…Normal transmission measurements are insufficiently sensitive, but the surface sensitivity can be greatly enhanced in attenuated total reflectance (ATR) [14]. The sensitivity enhancement depends on the angle of incidence, the thickness of the air gap and the dielectric constants of the ATR crystal and the film's substrate [15,16]. Here, we apply grazing angle attenuated total reflectance Fourier transform infrared (GATR-FTIR) to several high-k films of recent interest, Hf, Dy and Sc oxides, which were deposited by atomic vapour deposition (AVD) or atomic layer deposition (ALD) for high quality film growth with atomic precision.…”

“…Nonetheless, a single band at 695 cm À1 , in absence of a feature at 780 cm À1 , has been ascribed to cubic HfO 2 , because electron diffraction showed the presence of this phase in the samples [7]. The authors however did not demonstrate the absence of a portion amorphous phase, which is also reported to show a single band of similar shape in this wavenumber region of 690 cm À1 [3,16,24]. The presence or absence of a shoulder to the high wavenumber side of this band, is regarded as indicative of amorphous and cubic HfO 2 respectively [25].…”