A semiconductor-on-insulator structure including first and second layers
which are attached to one another either directly or through one or more
intermediate layers. The first layer includes a substantially single
crystal germanium semiconductor material while the second layer comprises
a glass or a glass-ceramic material having a linear coefficient thermal
of expansion (25-300.degree. C.) which is within the range of
+/-20.times.10.sup.-7/.degree. C. of the linear coefficient thermal of
expansion of the germanium first layer.