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Si/SiGe heterojunction bipolar transistor (HBT) structure: grown by ultra-high vacuum chemical vapor deposition (UHVCVD), was investigated with cross-sectional transmission electron microscopy (XTEM). It was determined that a very thin layer exists in the strained SiGe layer grown on Si; which is in parallel to the interface of SiGe and Si, and the position of thin layer changes with the intrinsic SiGe spacer width but not with the Ge content in the strained SiGe base layer. The base collector junction turn-on voltage of the HBT decreases from similar to 0.6 V to similar to 0.2 V when the spacer width decreases from 100 A to 75 A, and increases from similar to 0.2 V to similar to 0.4 V when the Ge content in the strained SiGe base layer decreases from 16\% to 10\%. A possible explanation for this phenomenon is that the Ge atom accumulates to form a very thin Ge-rich layer.

Si/SiGe heterojunction bipolar transistor (HBT) structure: grown by ultra-high vacuum chemical vapor deposition (UHVCVD), was investigated with cross-sectional transmission electron microscopy (XTEM). It was determined that a very thin layer exists in the strained SiGe layer grown on Si; which is in parallel to the interface of SiGe and Si, and the position of thin layer changes with the intrinsic SiGe spacer width but not with the Ge content in the strained SiGe base layer. The base collector junction turn-on voltage of the HBT decreases from similar to 0.6 V to similar to 0.2 V when the spacer width decreases from 100 A to 75 A, and increases from similar to 0.2 V to similar to 0.4 V when the Ge content in the strained SiGe base layer decreases from 16\% to 10\%. A possible explanation for this phenomenon is that the Ge atom accumulates to form a very thin Ge-rich layer.

Si/SiGe heterojunction bipolar transistor (HBT) structure: grown by ultra-high vacuum chemical vapor deposition (UHVCVD), was investigated with cross-sectional transmission electron microscopy (XTEM). It was determined that a very thin layer exists in the strained SiGe layer grown on Si; which is in parallel to the interface of SiGe and Si, and the position of thin layer changes with the intrinsic SiGe spacer width but not with the Ge content in the strained SiGe base layer. The base collector junction turn-on voltage of the HBT decreases from similar to 0.6 V to similar to 0.2 V when the spacer width decreases from 100 A to 75 A, and increases from similar to 0.2 V to similar to 0.4 V when the Ge content in the strained SiGe base layer decreases from 16\% to 10\%. A possible explanation for this phenomenon is that the Ge atom accumulates to form a very thin Ge-rich layer.

The self-planarization of deep trench with 2 micron thick field oxidation has been developed for self-aligned nitride bipolar integrated circuit fabrication. Trenches with geometry of 2 μm wide by 8 μm deep were achieved by anisotropic etching for isolating global buried collectors. They were then filled and planarized simply by a local oxidation of silicon (LOCOS) without polysilicon re-filling or etching back, while maintained a collector-to-collector leakage of 5 μa at 15 V. As proof-of-technology, arrays of trench-isolated bipolar transistors with cut-off frequency of 14 GHz were gold-metallized without extra planarization of the trench.

Sealed wedge-shaped silicon power triode have been fabricated by CMOS compatible technology. The fabricated field emitter has higher thermal and mechanical stability due to the Eiffel Tower shape. The sealed structure eliminates the needs for external vacuum pumping and improves the reliability and lifetime of the device. Anode current were demonstrated at anode voltage less than 4 volts.

Gated wedge-shaped field emitter has been fabricated by anisotropic etching and gold plating. The structure acquires merits of high emitter aspect ratio, sharp emitter tip and small gate-to-tip distance which are crucial in lowering the threshold voltage and increasing the emission efficiency of the device. The process is fairly simple with high processing latitude, therefore, is suitable for practical applications such as flat panel display and ultra-high frequency devices.

Sealed wedge-shaped silicon power triode have been fabricated by CMOS compatible technology. The fabricated field emitter has higher thermal and mechanical stability due to the Eiffel Tower shape. The sealed structure eliminates the needs for external vacuum pumping and improves the reliability and lifetime of the device. Anode current were demonstrated at anode voltage less than 4 volts.

Sealed wedge-shaped silicon power triode have been fabricated by CMOS compatible technology. The fabricated field emitter has higher thermal and mechanical stability due to the Eiffel Tower shape. The sealed structure eliminates the needs for external vacuum pumping and improves the reliability and lifetime of the device. Anode current were demonstrated at anode voltage less than 4 volts.

Gated wedge-shaped field emitter has been fabricated by anisotropic etching and gold plating. The structure acquires merits of high emitter aspect ratio, sharp emitter tip and small gate-to-tip distance which are crucial in lowering the threshold voltage and increasing the emission efficiency of the device. The process is fairly simple with high processing latitude, therefore, is suitable for practical applications such as flat panel display and ultra-high frequency devices.