High-hole mobility Si1-Ge (0.1 ≤ x ≤ 1) on an insulator formed by advanced solid-phase crystallization

Abstract

The grain size and hole mobility of polycrystalline Si1-xGex thin films formed on glass by solid-phase crystallization were significantly improved after preparing the amorphous precursors by heating the substrate. By just controlling the deposition temperature of the precursors (50-350 °C) for each SiGe composition, the grain size reached over 2 μm across the whole composition range. Reflecting the enlargement of the grain size, the hole mobility values were improved by approximately one order of magnitude. These values are comparable to those of single-crystal SiGe formed by Ge condensation and are the highest among SiGe on insulators synthesized at low temperature (<900 °C). The SiGe on insulator technology obtained in this study will greatly contribute to the development of SiGe-based electronic and optical devices.

Sb-doped crystallization of densified precursor for n-type polycrystalline Ge on an insulator with high carrier mobility

“…29 We recently found that the atomic density of amorphous Ge (a-Ge) significantly influenced subsequent SPC. [30][31][32] By using a densified a-Ge on a GeO 2 underlayer, we fabricated a poly-Ge layer with a hole mobility of 620 cm 2 /V s, 33 which greatly exceeds that of bulk-Si (430 cm 2 /V s). These achievements initiated the prospect of the development of inversion-type poly-Ge n-MOSFETs that surpass Si-MOSFETs.…”

Layer Exchange Synthesis of SiGe for Flexible Thermoelectric Generators: A Comprehensive Review

“…This behavior is consistent with the metal-free SPC of SiGe, where the LE temperatures are 100-300 °C lower than the SPC temperatures. [100][101][102][103] For all metal species and x, the LE temperatures reach 500 °C, which is the heat resistance temperature of engineering plastic films. The LE temperature is particularly low for Ge-Zn systems, which allows for the use of generalpurpose plastic films.…”

“…In general, undoped polycrystalline SiGe layers exhibit p-type conduction because of acceptor defects in Ge. [102,116,117] The addition of As in Zn, Ag, and Au allows n-type conduction control of SiGe layers at low x (≤0.3), though it is difficult for Ge-rich SiGe layers with a high density of acceptor defects (Figure 6c). Thus, the LE with impurity-doped metals enables the low-temperature synthesis of p-type Si 1-x Ge x with the whole x range, while the n-type is at low x (≤0.3).…”

Fabrication of a polycrystalline SiGe- and Ge-on-insulator by Ge condensation of amorphous SiGe on a SiO2/Si substrate

“…With an 'on-insulator' structure, the performance of Ge electronic devices can be further improved through reducing parasitic capacitance and leakage current. Many techniques have been developed to obtain Ge-on-insulator (GOI) platforms such as wafer bonding [3], smart-cut [4], solid-phase crystallization [5,6], and Ge condensation [7,8]. Among them, Ge condensation, which uses cyclic oxidation and annealing of low-Ge-content SiGe-on-insulator (SGOI) material at high temperature (≥ 900 • C), can be used to fabricate high quality SGOI with a desired Ge content up to 1.0.…”