1. Technical Field
The present invention relates to a method and structure for conductively coupling electrical structures to a semiconductor device located under a buried oxide layer.
2. Related Art
An electrostatic discharge device (ESD) located within a substrate and above a buried oxide layer is surrounded by thermally insulative material in silicon-on-insulator (SOI) structures. For example, the ESD device may be surrounded by the buried oxide layer on the bottom, small trench isolations on the sides, and interlevel dielectric on the top. An electrostatic discharge device must be able to handle large electrical currents that result from static discharge, from a human body or the environment onto an integrated circuit coupled to, or integral with, the substrate. Such large electrical currents generate substantial heat which cannot be effectively dissipated away from the ESD device, because of the surrounding electrically and thermally insulative material.
A method and structure is needed for effectively dissipating heat during an electrostatic discharge event on SOI.
The present invention provides an electronic structure, comprising:
a bulk semiconductor substrate having a semiconductor device, wherein the semiconductor device includes M diffusions, wherein M is at least 2, wherein a first diffusion of the M diffusions is a P+ diffusion, and wherein a second diffusion of the M diffusions is a N+ diffusion;
a silicon-on-insulator (SOI) structure on the bulk semiconductor substrate, wherein the SOI structure includes an insulator layer on the bulk semiconductor substrate and a semiconductor layer on the insulator layer; and
M conductive plugs self-aligned with the M diffusions and extending through a portion of the SOI layer such that an end of each conductive plug is in conductive contact with a corresponding diffusion of the M diffusions.
The present invention provides a method for forming an electronic structure, comprising the steps of:
providing a bulk semiconductor substrate;
forming a silicon-on-insulator (SOI) structure on the bulk semiconductor substrate, wherein the SOI structure includes an insulator layer on the bulk semiconductor substrate and a semiconductor layer on the insulator layer;
forming a trench structure through the SOI layer, wherein an end of the trench structure is interfaced with the bulk semiconductor substrate;
forming a semiconductor device in the bulk semiconductor substrate by use of the trench structure, wherein the semiconductor device includes M diffusions, wherein M is at least 2, wherein a first diffusion of the M diffusions is a P+ diffusion, and wherein a second diffusion of the M diffusions is a N+ diffusion; and
forming M conductive plugs self-aligned with the M diffusions and extending through a portion of the SOI layer such that an end of each conductive plug is in conductive contact with a corresponding diffusion of the M diffusions.
The present invention provides a method and structure for effectively dissipating heat during an electrostatic discharge event.