Effects of Ge Content on the Oxidation Behavior of Poly-Si[sub 1−x]Ge[sub x] Layers for Gate Electrode Application

Abstract

Oxidation characteristics of nonpatterned and patterned poly-SiGe layers were evaluated to confirm the feasibility for the application of poly-SiGe to the gate electrode. Characterization of poly-SiGe after oxidation was performed using atomic force microscopy ͑AFM͒, X-ray photoelectron spectroscopy ͑XPS͒, cross-sectional transmission electron microscopy ͑TEM͒, and energy-dispersive X-ray spectroscopy ͑EDS͒. The oxide thickness on poly-SiGe layer increased with increasing Ge content, while that on poly-SiGe ͑Ge 20%͒ sample was comparable to that of poly-Si ͑Ge 0%͒. When the Ge content was more than 40%, two different oxide layers were observed on poly-SiGe. Intensive analyses revealed that the oxide layers were composed of SiO 2 -rich mixed oxide (SiO 2 ͑GeO 2 ͒) and GeO 2 -rich mixed oxide (GeO 2 ͑SiO 2 ͒͒. For the patterned poly-SiGe sample, the oxidation characteristics were similar to those of nonpatterned sample. The best sidewall oxide profile was obtained in poly-SiGe ͑Ge 20%͒ sample. Because the sidewall oxide thickness is too thick for poly-SiGe sample with more than 40% of Ge, poly-SiGe ͑Ge 20%͒ is believed to be the most suitable candidate for gate electrode material.

Photonic effects during low-temperature ultraviolet-assisted oxidation of SiGe

“…19,20 For irradiation times longer than 90 min, there is a sudden increase in the size of the oxidized Ge peak simultaneous with a corresponding decrease of the unoxidized Ge peak. The sample oxidized for 122 min exhibits surface Si and Ge oxidized peaks located at 103.5 eV and 33.6 eV, which is very similar to those recorded for thick stoichiometric oxides, 3,8,10,[15][16][17] i.e., Si 4ϩ and Ge 4ϩ . The amount of Si and Ge atoms bound in suboxides was estimated to be ϳ5% and ϳ20% after 30-min oxidation and decreased for longer oxidation times.…”

Oxidation of RuAl and NiAl Thin Films: Evolution of Surface Morphology and Electrical Resistance

“…The roughness of the cosputtered films was not measured, but from the crosssectional TEM images, it is expected to be slightly higher than that of the annealed multilayer films. The film deposition was not optimized in order to decrease the roughness further, but even without optimization, these values are less than what is seen in the literature for SiGe films (1.8-5.4 nm rms) [55], [56]. Annealing of the multilayer samples prior to oxidation caused no significant change in the rms roughness for a multilayer with a 33-nm wavelength.…”

Programming Speed Enhancement by NH[sub 3] Plasma Nitridation of Tunneling Oxide for Ge Nanocrystals Memory

“…In other words, Ge atoms may segregate from Si x Ge 1−x or SiGe x O y films when the annealing temperature approximates the Ge melting point. 19 Another possible reason for no Ge-O bonding in some samples is the fact that SiO 2 has lower free energy ͑⌬G = −732 kJ/mol͒ than GeO 2 ͑⌬G = −376 kJ/mol͒, 20 which implies that the Si-O bonds are formed more easily than the Ge-O bonds at elevated temperatures. To verify the existence of nitrogen in the TO film, XPS depth profiles of the Si 2p spectra for A-0, A-1, and A-3 samples were obtained and are shown in Fig.…”