MOVPE growth of GaAs on Ge substrates by inserting a thin low temperature buffer layer

Abstract

High quality GaAs layers have been grown by low pressure MOVPE on Ge(001) and Ge(001) 9° off oriented in [110] direction by using a thin low temperature (LT) GaAs layer. Investigations of the initial growth step were performed at different V/III ratios and temperatures. To show the good buffer layer quality solar cell structures were grown on off oriented n-Ge(001) and n-GaAs(001) substrates. The surface morphology was studied by atomic force microscopy which showed the step-flow growth mode on 1.2 µm thick GaAs/Ge structures. The crystalline qualities of this structures and the smooth surface morphology were investigated by double crystal X-ray diffraction (XRD) and atomic force microscopy (AFM).

Effects of Al0.3Ga0.7As interlayer with pulsed atomic layer epitaxy on heterogeneous integration of GaAs/Ge grown by MOCVD

“…1 68 nm, respectively, which suggests that the GaAs films with AlAs/GaAs PALE interlayer could get smoother surface morphology than those growth without interlayer and with AlGa/AlGaAs PALE interlayer. Compared with RMS roughnesses of 12.47 nm and 1.5 nm in 10 lm  10 lm scan area reported by Hudait et al [13] and Scholz et al [14], significant improvement in surface root-mean-square (RMS) roughness of GaAs epilayers grown on 9°offcut Ge substrate has been obtained in our work. The cross sectional transmission electron microscope (XTEM) is employed to further study the microstructures of all these samples.…”

“…Even though the mismatches of lattice constants and thermal expansion coefficients between GaAs and Ge are negligible, challenges remain in growing GaAs directly on Ge substrate [2], mainly due to the formation of anti-phase domains (APDs) when polar materials GaAs grown on nonpolar materials Ge [5,6], and the atomic interdiffusion near the GaAs/Ge interface [1,[7][8][9]. For the former, it has been well established that under proper growth conditions, the APDs can be eliminated by the adoption of off-cut Ge substrates [10][11][12][13][14][15]. For the later, Chia et al demonstrated that the interdiffusion could be effectively blocked by introducing an interlayer with high bonding energy such as Al x Ga 1Àx As [16,17].…”

III-V Compounds-on-Si: Heterostructure Fabrication, Application and Prospects

“…The best results in FWHM of GaAs films are observed when they are grown on the Ge or GOI wafers (Geon-Insulator, -Ge on Si by bonding, for more details on such platform see Chapter 3). Thus, the FWHM values of GaAs/Ge and GaAs/GOI borrowed from Scholtz et al [37] and Loubyshev et al [38] are hit on or near of the theoretical dependence (Fig. 2).…”

The role of AsH3 partial pressure on anti-phase boundary in GaAs-on-Ge grown by MOCVD – Application to a 200mm GaAs virtual substrate

“…Two temperature ranges have been reported for the GaAs buffer layer that allows for the growth of APB-free GaAs layers. One is in the [350-550°C] range [4,[14][15][16][17] and the second one is in the [600-725°C range] [7,[17][18][19][20]. Between these two temperature ranges, growth of a mixed distribution of GaAs domains occurs, leading to the formation of numerous APB [17].…”