%0 Conference Paper %1 9597145 %A Sigle, E. %A Weißhaupt, D. %A Oehme, M. %A Funk, H. S. %A Schwarz, D. %A Berkmann, F. %A Schulze, J. %B 2021 44th International Convention on Information, Communication and Electronic Technology (MIPRO) %D 2021 %K iht j.schulze.iht journal professional_meetings %P 40-44 %R 10.23919/MIPRO52101.2021.9597145 %T Strained Ge Channels with High Hole Mobility Grown on Si Substrates by Molecular Beam Epitaxy %X Strained modulation-doped quantum wells (QW) offer a huge potential for semiconductor device applications due to their high mobility. The material Ge is particularly interesting here, exhibiting the highest bulk hole-mobility of all known semiconductors. However, the growth for Ge QW structures is quite complex and a special virtual substrate (VS) technique is needed. The VS is commonly grown with thicknesses of over <tex>$1\ m$</tex>, making it difficult for integration with other devices on a single chip. In this paper, we report on the growth of a 15 nm thick strained Ge QW on top of a <tex>$Si_1-xGe_x$</tex> VS and <tex>$Si_0.2Ge_0.8$</tex> buffer layer, using Molecular Beam Epitaxy. The <tex>$Si_1-xGe_x$</tex> VS is grown by deposition of 100 nm Ge with a subsequent high-temperature annealing step, followed by a 100 nm thick <tex>$Si_0.2Ge_0.8$</tex> buffer layer. The resulting two-dimensional hole gas reaches a hole mobility of over <tex>$810^4cm^2V^-1s^-1$</tex> with a corresponding sheet carrier density of <tex>$5.710^11cm^-2$</tex> at 8 K. The Ge QW is further analysed, and comparing it to a sample with a higher VS thickness, a possible limitation of the mobility due to background doping is being discussed. These results show that complementary metal-oxide-semiconductor (CMOS) compatible device integration of the Ge QW is possible, thin buffer layers suffice for the mobilities achieved and background doping limits the low-temperature mobility.

@inproceedings{9597145, abstract = {Strained modulation-doped quantum wells (QW) offer a huge potential for semiconductor device applications due to their high mobility. The material Ge is particularly interesting here, exhibiting the highest bulk hole-mobility of all known semiconductors. However, the growth for Ge QW structures is quite complex and a special virtual substrate (VS) technique is needed. The VS is commonly grown with thicknesses of over <tex>$1\ \mu \mathrm{m}$</tex>, making it difficult for integration with other devices on a single chip. In this paper, we report on the growth of a 15 nm thick strained Ge QW on top of a <tex>$\mathbf{Si_{1-x}}\mathbf{Ge_{x}}$</tex> VS and <tex>$\mathbf{Si_{0.2}}\mathbf{Ge_{0.8}}$</tex> buffer layer, using Molecular Beam Epitaxy. The <tex>$\mathbf{Si_{1-x}}\mathbf{Ge_{x}}$</tex> VS is grown by deposition of 100 nm Ge with a subsequent high-temperature annealing step, followed by a 100 nm thick <tex>$\mathbf{Si_{0.2}}\mathbf{Ge_{0.8}}$</tex> buffer layer. The resulting two-dimensional hole gas reaches a hole mobility of over <tex>$\boldsymbol{8\cdot 10^{4}\text{cm}^{2}\mathrm{V}^{-1}\mathrm{s}^{-1}}$</tex> with a corresponding sheet carrier density of <tex>$\boldsymbol{5.7\cdot 10^{11}\text{cm}^{-2}}$</tex> at 8 K. The Ge QW is further analysed, and comparing it to a sample with a higher VS thickness, a possible limitation of the mobility due to background doping is being discussed. These results show that complementary metal-oxide-semiconductor (CMOS) compatible device integration of the Ge QW is possible, thin buffer layers suffice for the mobilities achieved and background doping limits the low-temperature mobility.}, added-at = {2021-11-23T12:20:14.000+0100}, author = {Sigle, E. and Weißhaupt, D. and Oehme, M. and Funk, H. S. and Schwarz, D. and Berkmann, F. and Schulze, J.}, biburl = {https://puma.ub.uni-stuttgart.de/bibtex/2b09be7fa8fbc5263b07995e7fcaaf91c/ihtpublikation}, booktitle = {2021 44th International Convention on Information, Communication and Electronic Technology (MIPRO)}, description = {Strained Ge Channels with High Hole Mobility Grown on Si Substrates by Molecular Beam Epitaxy | IEEE Conference Publication | IEEE Xplore}, doi = {10.23919/MIPRO52101.2021.9597145}, interhash = {a93d331bcba160392d5af17934540429}, intrahash = {b09be7fa8fbc5263b07995e7fcaaf91c}, issn = {2623-8764}, keywords = {iht j.schulze.iht journal professional_meetings}, month = {Sep.}, pages = {40-44}, timestamp = {2021-11-23T11:20:14.000+0100}, title = {Strained Ge Channels with High Hole Mobility Grown on Si Substrates by Molecular Beam Epitaxy}, year = 2021 }