Radio frequency isolation for SOI transistors

摘要

According to one example embodiment, a structure includes at least one SOI (semiconductor-on-insulator) transistor situated over a buried oxide layer, where the buried oxide layer overlies a bulk substrate. The structure further includes an electrically charged field control ring situated over the buried oxide layer and surrounding the at least one SOI transistor. A width of the electrically charged field control ring is greater than a thickness of the buried oxide layer. The electrically charged field control ring reduces a conductivity of a surface portion of the bulk substrate underlying the field control ring, thereby reducing RF coupling of the at least one SOI transistor through the bulk substrate. The structure further includes an isolation region situated between the electrically charged field control ring and the at least one SOI transistor. A method to achieve and implement the disclosed structure is also provided.

主权项

1. A structure comprising:
at least one SOI (semiconductor-on-insulator) transistor situated in a silicon layer over a buried oxide layer, said buried oxide layer having a thickness greater than a thickness of the silicon layer and overlying a bulk substrate, the at least one SOI transistor having a source and a drain in contact with the buried oxide layer; and a field control ring formed in the silicon layer, above said buried oxide layer and surrounding said at least one SOI transistor, said field control ring coupled to a bias voltage of non-zero voltage to provide a charge to the field control ring to generate an electrical field that creates a resistive surface portion on said bulk substrate underlying said field control ring, wherein a width of said field control ring is greater than said thickness of said buried oxide layer by a factor of between 3.0 and about 10.0.