SiGe transistor, varactor and p-i-n velocity saturated ballasting element for BiCMOS peripheral circuits and ESD networks
AssigneeInternational Business Machines Corporation
InventorSteven Howard Voldman
Life of this patent
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Abstract
An SiGe device configured to exhibit high velocity saturation resistance characteristic for buffering large voltages at low currents, wherein for circuit applications, the SiGe device is connected in series with a circuit element for protection of the circuit element. Advantageously, the device may be exploited as a buffer element providing ESD circuit protection for receiver devices, power supply clamp circuits and I/O driver circuits.
Claims23
An SiGe device configured to exhibit high velocity saturation resistance characteristic for buffering large voltages at low currents, wherein for circuit applications, said SiGe device is connected in series with a circuit element for protection of said circuit element.
An SiGe device comprising:
- a semiconductor substrate of a first conductivity type;
- a doped collector region formed on top of said semiconductor substrate, said doped collector region of second conductivity type;
- and,
- a base region of said first conductivity type overlaying said doped collector region,
- wherein said device is configured to exhibit high velocity saturation resistance characteristic for buffering large voltages at low currents.
An SiGe device comprising:
- a semiconductor substrate of a first conductivity type;
- a doped collector region formed on top of said semiconductor substrate, said doped collector region of second conductivity type;
- a polysilicon germanium layer of said first conductivity type forming a base region overlaying said doped collector region, said polysilicon germanium layer grown by low temperature epitaxy,
- an dielectric film formed on said base region;
- and,
- a polysilicon germanium layer of said second conductivity type forming an emitter region overlaying said dielectric film in alignment with said base region, said doped polysilicon germanium layer of said first conductivity type including an emitter region formed of said second conductivity type in contact with said emitter layer,
- wherein said SiGe device base region is electrically connected with said emitter base region, said collector and base regions forming a base-collector diode, said device being selectively doped to exhibit high velocity saturation resistance characteristic for buffering large voltages at low currents.
Dependencies are inferred from the claim text.