Design structure with a deep sub-collector, a reach-through structure and trench isolation

A device comprising:

• a deep sub-collector located in a first epitaxial layer;
• a doped region located in a second epitaxial layer, which is above the first epitaxial layer;
• a reach-through structure penetrating from a surface of the device through the first and second epitaxial layers to the deep sub-collector;
• a trench isolation structure penetrating from a surface of the device into the reach-through structure and surrounding the doped region;
• and
• a diode, wherein the diode is a Schottky barrier diode, a PIN diode, or a hyper-abrupt varactor diode.

A method of forming a structure, comprising:

• forming a first epitaxial layer on a substrate;
• forming a deep sub-collector in the first epitaxial layer;
• forming a second epitaxial layer on the first epitaxial layer;
• forming a doped region over the deep sub-collector;
• forming a reach-through in the first and second epitaxial layers which is in electrical contact with the deep sub-collector;
• forming a trench isolation structure penetrating into the reach through, in physical contact with the doped region, the deep subcollector, and the reach-through, and between the doped region and the reach-through in order to electrically isolate the doped region from the reach-through.

A device comprising:

• a deep sub-collector located in a first epitaxial layer;
• a doped region located in a second epitaxial layer, which is above the first epitaxial layer;
• a reach-through structure penetrating from a surface of the device through the first and second epitaxial layers to the deep sub-collector;
• a trench isolation structure penetrating from a surface of the device into the reach-through structure and surrounding the doped region;
• a shallow trench isolation structure located inside a surface of the reach-through structure, wherein the trench isolation structure penetrates through the shallow trench isolation structure to the deep sub-collector;
• and
• a salicide layer located on a surface of the device above and directly in contact with the doped region.

A method of forming a structure, comprising:

• forming a first epitaxial layer on a substrate;
• forming a deep sub-collector in the first epitaxial layer;
• forming a second epitaxial layer on the first epitaxial layer;
• forming a device over the deep sub-collector;
• forming a reach-through in the first and second epitaxial layers which is in electrical contact with the deep sub-collector;
• forming a trench isolation structure penetrating into the reach through, in contact with the device, the deep subcollector, and the reach-through and between the device and the reach-through in order to electrically isolate the device from the reach-through;
• forming a shallow trench isolation structure inside a surface of the reach-through structure, wherein the trench isolation structure penetrates through the shallow trench isolation structure to the deep sub-collector;
• forming a diode, wherein the diode is a Schottky barrier diode, a PIN diode, or a hyper-abrupt varactor diode;
• and
• forming a salicide layer on a surface of the device above and directly in contact with the doped region,
• wherein the doped region is a low-doped N− or N+ region or a P+ or P− diffusion,
• wherein the reach-through comprises a stacked reach-through which acts as a cathode, and
• wherein the doped region comprises a P+ diffusion region which acts as an anode.