as a hardmask as well as a polish stop layer the thickness of hardmask 18 is not critical to the present invention but typically hardmask 18 has a thickness of from about 50 to about 100 nm the resultant structure including pad oxide layer 16 and hardmask 18 is shown for example in fig2 it is noted that in fig2 as well as the remaining drawings si containing substrate 10 of the initial soi wafer has been omitted for clarity the si containing substrate is intended to be present however in each of the drawings the thickness of layer 14 illustrated in fig2 has been shown to be thicker than the original thickness of layer 14 in fig1 for clarity fig3 shows the structure that is formed after various isolation regions including shallow trench isolation region 20 and deep trench isolation regions 22 are formed into the structure shown in fig2 as shown the shallow trench isolation region is formed through hardmask 18 pad oxide layer 16 and into a portion of si containing layer 14 the deep trench isolation regions on the other hand are formed through hardmask 18 pad oxide layer 16 and si containing layer 14 stopping on or in an upper surface of buried oxide region 12 it is noted that the actual number of shallow trench isolation regions and deep trench isolation regions may exceed the number shown in the drawings in such circumstances two nearby deep trench isolation regions will flank each shallow trench isolation region present in the structure the trench isolation regions both.