title: Electrical isolation of dislocations in Ge layers on Si(001) substrates through CMOS-compatible suspended structures.
abstract: Suspended crystalline Ge semiconductor structures are created on a Si(001) substrate by a combination of epitaxial growth and simple patterning from the front surface using anisotropic underetching. Geometric definition of the surface Ge layer gives access to a range of crystalline planes that have different etch resistance. The structures are aligned to avoid etch-resistive planes in making the suspended regions and to take advantage of these planes to retain the underlying Si to support the structures. The technique is demonstrated by forming suspended microwires, spiderwebs and van der Pauw cross structures. We finally report on the low-temperature electrical isolation of the undoped Ge layers. This novel isolation method increases the Ge resistivity to 280 Ω cm at 10 K, over two orders of magnitude above that of a bulk Ge on Si(001) layer, by removing material containing the underlying misfit dislocation network that otherwise provides the main source of electrical conduction.
authors.affiliation: Physics Department, Warwick University, Coventry CV47AL, UK.
authors.forename: Vishal Ajit
authors.initials: VA
authors.lastname: Shah
authors.affiliation: Physics Department, Warwick University, Coventry CV47AL, UK.
authors.forename: Maksym
authors.initials: M
authors.lastname: Myronov
authors.affiliation: Physics Department, Warwick University, Coventry CV47AL, UK.
authors.forename: Chalermwat
authors.initials: C
authors.lastname: Wongwanitwatana
authors.affiliation: Physics Department, Warwick University, Coventry CV47AL, UK.
authors.forename: Lewis
authors.initials: L
authors.lastname: Bawden
authors.affiliation: Physics Department, Warwick University, Coventry CV47AL, UK.
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Prest
authors.affiliation: Physics Department, Warwick University, Coventry CV47AL, UK.
authors.forename: James S
authors.initials: JS
authors.lastname: Richardson-Bullock
authors.affiliation: Physics Department, Warwick University, Coventry CV47AL, UK.
authors.forename: Stephen
authors.initials: S
authors.lastname: Rhead
authors.affiliation: Physics Department, Warwick University, Coventry CV47AL, UK.
authors.forename: Evan H C
authors.initials: EH
authors.lastname: Parker
authors.affiliation: Physics Department, Warwick University, Coventry CV47AL, UK.
authors.forename: Terrance E
authors.initials: TE
authors.lastname: Whall
authors.affiliation: Physics Department, Warwick University, Coventry CV47AL, UK.
authors.forename: David R
authors.initials: DR
authors.lastname: Leadley
keywords: Ge; RP-CVD; TMAH; anisotropic; conduction; dislocation; etch; germanium