Low Temperature (180°C) Growth of Smooth Surface Germanium Epilayers on Silicon Substrates Using Electron Cyclotron Resonance Chemical Vapor Deposition

Abstract

This paper describes a new method to grow thin germanium (Ge) epilayers (40 nm) on c-Si substrates at a low growth temperature of 180°C using electron cyclotron resonance chemical vapor deposition (ECR-CVD) process. The full width at half maximum (FWHM) of the Ge (004) in X-ray diffraction pattern and the compressive stain in a Ge epilayer of 683 arcsec and 0.12% can be achieved. Moreover, the Ge/Si interface is observed by transmission electron microscopy to demonstrate the epitaxial growth of Ge on Si and the surface roughness is 0.342 nm. The thin-thickness and smooth surface of Ge epilayer grown on Si in this study is suitable to be a virtual substrate for developing the low cost and high efficiency III-V/Si tandem solar cells in our opinion. Furthermore, the low temperature process can not only decrease costs but can also reduce the restriction of high temperature processes on device manufacturing.

Monolithic Metal–Semiconductor–Metal Heterostructures Enabling Next-Generation Germanium Nanodevices

“… 34 − 36 The measured full width at half-maximum of the Ge mode (Γ = 5.1 cm –1 ) in the spectrum is only ∼1.7 cm –1 larger than in the bulk (Γ = 3.4 cm –1 ), 37 which indicates a pure Ge segment of good crystal quality. 38 …”

“…To check the internal stress in the Ge segment, probably as part of the manufacturing process, we performed μ-Raman measurements on a 2 μm-wide and 1.5 μm-long Ge segment shown in the inset of Figure a. The Raman spectrum in the main plot reveals two distinct peaks assigned to the Stokes transverse optical (TO) modes of Ge at about 301 cm –1 and the supporting Si handle wafer at 520 cm –1 . − The measured full width at half-maximum of the Ge mode (Γ = 5.1 cm –1 ) in the spectrum is only ∼1.7 cm –1 larger than in the bulk (Γ = 3.4 cm –1 ), which indicates a pure Ge segment of good crystal quality …”

“…34−36 The measured full width at half-maximum of the Ge mode (Γ = 5.1 cm −1 ) in the spectrum is only ∼1.7 cm −1 larger than in the bulk (Γ = 3.4 cm −1 ), 37 which indicates a pure Ge segment of good crystal quality. 38 To evaluate the optical and electrical properties of the monolithic Al-Ge-Al heterostructures, we performed photoluminescence (PL) and common I/V measurements. The right inset of Figure 4a shows exemplarily a comparison of the room-temperature near-infrared PL spectra obtained at the Ge segment, the bare device layer, and the Si handle wafer of the GeOI substrate.…”

Heteroepitaxy of High-Mobility Germanium on Sapphire (0001) with Magnetron Sputtering

“…For Ge thin-film characterization, Raman spectroscopy is one of the most commonly used tools to evaluate its crystalline quality, ,,,, i.e., a Raman spectrum can be used to do a qualitative crystalline analysis based on the peak characteristics such as the peak position and its FWHM value. Higher peak intensity with a smaller FWHM value for a germanium peak indicates better crystalline quality with less defect density and larger crystalline domains. , Figure shows the Raman spectra for four GOS samples: 500 nm and 2.0 μm thick films before and after 850 °C thermal annealing.…”

Strain-Controlled of Compressive/Tensile Ge Epilayers on Si by Electron Cyclotron Resonance Chemical Vapor Deposition

“…In this study, we used ECR-CVD to grow Ge epilayers on n-type <100> CZ silicon wafers with a resistivity of 1-10 -cm z E-mail: 102389003@cc.ncu.edu.tw diced at a low growth temperature of 220 • C. The ECR-CVD process provides a number of advantages for the growth of films, such as high crystallinity, less ion damage to the surface, and high deposition rates. 23,24 During process, we modulate the process pressure and main coil current to control the strain in the Ge epilayers. The main coil current is used to control the plasma position in the ECR chamber.…”