Abstract: Methods for fabricating a bipolar junction transistor (BJT) are provided. A method includes forming a collector region, forming base regions over the collector region, and forming emitter regions over the base regions. The method further includes forming base dielectric layers over the collector region and on opposite sides of the base regions, forming base conductive layers over the base dielectric layers and on the opposite sides of the base regions, and forming base contacts over the base conductive layers. The top surface of the collector region is coplanar with bottom surfaces of the base regions and bottom surfaces of the base dielectric layers. The base contacts are divided into a first group of base contacts disposed between the base regions and a second group of base contacts disposed between the base regions and the STI region.

Abstract: Structures and methods for trench isolation are disclosed. In one example, a silicon-on-insulator (SOI) structure is disclosed. The SOI structure includes: a substrate, a dielectric layer and a polysilicon region. The substrate includes: a handle layer, an insulation layer arranged over the handle layer, a buried layer arranged over the insulation layer, and a trench extending downward from an upper surface of the buried layer and terminating in the handle layer. The dielectric layer is located on a bottom surface of the trench and contacting the handle layer. The polysilicon region is located in the trench and contacting the dielectric layer.

Abstract: Structures and methods for reducing process charging damages are disclosed. In one example, a silicon-on-insulator (SOI) structure is disclosed. The SOI structure includes: a substrate, a polysilicon region and an etch stop layer. The substrate includes: a handle layer, an insulation layer arranged over the handle layer, and a buried layer arranged over the insulation layer. The polysilicon region extends downward from an upper surface of the buried layer and terminates in the handle layer. The etch stop layer is located on the substrate. The etch stop layer is in contact with both the substrate and the polysilicon region.

Abstract: A method of forming a semiconductor device structure includes forming a first resist structure over a hard mask. The method further includes patterning the first resist structure to form a trench therein. The method further includes performing a first hydrogen plasma treatment to the patterned first resist structure, wherein the first hydrogen plasma treatment is configured to smooth sidewalls of the trench. The method further includes patterning the hard mask using the patterned resist structure as an etch mask. The method further includes forming a second resist structure over the patterned hard mask. The method further includes patterning the second resist structure to form an opening therein. The method further includes performing a second hydrogen plasma treatment to the patterned second resist structure. The method further includes patterning the patterned hard mask using the patterned second resist structure as a second etch mask.

Abstract: The reflectance of a low-reflectance alignment mark is increased by coating the alignment mark with a high-reflectance film layer. This improves the strength of the light signal and reduces variation in the light signal.

Abstract: Structures and methods for trench isolation are disclosed. In one example, a silicon-on-insulator (SOI) structure is disclosed. The SOI structure includes: a substrate, a dielectric layer and a polysilicon region. The substrate includes: a handle layer, an insulation layer arranged over the handle layer, a buried layer arranged over the insulation layer, and a trench extending downward from an upper surface of the buried layer and terminating in the handle layer. The dielectric layer is located on a bottom surface of the trench and contacting the handle layer. The polysilicon region is located in the trench and contacting the dielectric layer.

Abstract: Structures and methods for reducing process charging damages are disclosed. In one example, a silicon-on-insulator (SOI) structure is disclosed. The SOI structure includes: a substrate, a polysilicon region and an etch stop layer. The substrate includes: a handle layer, an insulation layer arranged over the handle layer, and a buried layer arranged over the insulation layer. The polysilicon region extends downward from an upper surface of the buried layer and terminates in the handle layer. The etch stop layer is located on the substrate. The etch stop layer is in contact with both the substrate and the polysilicon region.

Abstract: A semiconductor device includes a semiconductor substrate having a first region and a second region, insulators, gate stacks, and first and second S/Ds. The first and second regions respectively includes at least one first semiconductor fin and at least one second semiconductor fin. A width of a middle portion of the first semiconductor fin is equal to widths of end portions of the first semiconductor fin. A width of a middle portion of the second semiconductor fin is smaller than widths of end portions of the second semiconductor fin. The insulators are disposed on the semiconductor substrate. The first and second semiconductor fins are sandwiched by the insulators. The gate stacks are over a portion of the first semiconductor fin and a portion of the second semiconductor fin.

Abstract: The reflectance of a low-reflectance alignment mark is increased by coating the alignment mark with a high-reflectance film layer. This improves the strength of the light signal and reduces variation in the light signal.

Abstract: Disclosed is a method for forming a crystalline protective polysilicon layer which does not create defective voids during subsequent processes so as to provide effective protection to devices underneath. In one embodiment, a method for forming a semiconductor device, includes: depositing a protective coating on a first polysilicon layer; forming an epitaxial layer on the protective coating; and depositing a second polysilicon layer over the epitaxial layer, wherein the protective coating comprises a third polysilicon layer, wherein the third polysilicon layer is deposited at a first temperature in a range of 600-700 degree Celsius, and wherein the third polysilicon layer in the protect coating is configured to protect the first polysilicon layer when the second polysilicon layer is etched.

Abstract: A method of forming a semiconductor device structure includes forming a resist structure over a substrate, the resist structure includes an anti-reflective coating (ARC) layer and a photoresist layer over the ARC layer. The method further includes patterning the photoresist layer to form a trench therein. The method further includes performing a hydrogen plasma treatment to the patterned photoresist layer, wherein the hydrogen plasma treatment is configured to smooth sidewalls of the trench, and the hydrogen plasma treatment is performed at a temperature ranging from about 200° C. to about 600° C. The method further includes patterning the ARC layer using the patterned photoresist layer as a etch mask.

Abstract: A semiconductor device includes a semiconductor substrate having a first region and a second region, insulators, gate stacks, and first and second S/Ds. The first and second regions respectively includes at least one first semiconductor fin and at least one second semiconductor fin. A width of a middle portion of the first semiconductor fin is equal to widths of end portions of the first semiconductor fin. A width of a middle portion of the second semiconductor fin is smaller than widths of end portions of the second semiconductor fin. The insulators are disposed on the semiconductor substrate. The first and second semiconductor fins are sandwiched by the insulators. The gate stacks are over a portion of the first semiconductor fin and a portion of the second semiconductor fin. The first and second S/Ds respectively covers another portion of the first semiconductor fin and another portion of the second semiconductor fin.

Abstract: Disclosed is a method for forming a crystalline protective polysilicon layer which does not create defective voids during subsequent processes so as to provide effective protection to devices underneath. In one embodiment, a method for forming a semiconductor device, includes: depositing a protective coating on a first polysilicon layer; forming an epitaxial layer on the protective coating; and depositing a second polysilicon layer over the epitaxial layer, wherein the protective coating comprises a third polysilicon layer, wherein the third polysilicon layer is deposited at a first temperature in a range of 600-700 degree Celsius, and wherein the third polysilicon layer in the protect coating is configured to protect the first polysilicon layer when the second polysilicon layer is etched.

Abstract: Structures and methods for trench isolation are disclosed. In one example, a silicon-on-insulator (SOI) structure is disclosed. The SOI structure includes: a substrate, a dielectric layer and a polysilicon region. The substrate includes: a handle layer, an insulation layer arranged over the handle layer, a buried layer arranged over the insulation layer, and a trench extending downward from an upper surface of the buried layer and terminating in the handle layer. The dielectric layer is located on a bottom surface of the trench and contacting the handle layer. The polysilicon region is located in the trench and contacting the dielectric layer.

Abstract: Structures and methods for reducing process charging damages are disclosed. In one example, a silicon-on-insulator (SOI) structure is disclosed. The SOI structure includes: a substrate, a polysilicon region and an etch stop layer. The substrate includes: a handle layer, an insulation layer arranged over the handle layer, and a buried layer arranged over the insulation layer. The polysilicon region extends downward from an upper surface of the buried layer and terminates in the handle layer. The etch stop layer is located on the substrate. The etch stop layer is in contact with both the substrate and the polysilicon region.

Abstract: Structures and methods for reducing process charging damages are disclosed. In one example, a silicon-on-insulator (SOI) structure is disclosed. The SOI structure includes: a substrate, a polysilicon region and an etch stop layer. The substrate includes: a handle layer, an insulation layer arranged over the handle layer, and a buried layer arranged over the insulation layer. The polysilicon region extends downward from an upper surface of the buried layer and terminates in the handle layer. The etch stop layer is located on the substrate. The etch stop layer is in contact with both the substrate and the polysilicon region.

Abstract: A method of forming a semiconductor device structure includes forming a resist structure over a substrate, the resist structure includes an anti-reflective coating (ARC) layer and a photoresist layer over the ARC layer. The method further includes patterning the photoresist layer to form a trench therein. The method further includes performing a hydrogen plasma treatment to the patterned photoresist layer, wherein the hydrogen plasma treatment is configured to smooth sidewalls of the trench, and the hydrogen plasma treatment is performed at a temperature ranging from about 200° C. to about 600° C. The method further includes patterning the ARC layer using the patterned photoresist layer as a etch mask.

Abstract: Bipolar junction transistor (BJT) structures are provided. A BJT structure includes a semiconductor substrate, a collector region formed in the semiconductor substrate, a base region formed over the collector region, an emitter region formed over the collector region, a ring-shaped shallow trench isolation (STI) region formed in the collector region, and a base dielectric layer formed over the collector region and on opposite sides of the base region. The base dielectric layer is surrounded by an inner side wall of the ring-shaped STI region.

Abstract: A method of forming a semiconductor device structure is provided. The method includes forming a resist structure over a substrate. The resist structure includes an anti-reflective coating (ARC) layer and a photoresist layer over the ARC layer. The method further includes patterning the photoresist layer to form a trench therein. The method further includes performing a hydrogen plasma treatment to the patterned photoresist layer. The hydrogen plasma treatment is configured to smooth sidewalls of the trench without etching the ARC layer. The method further includes patterning the ARC layer using the patterned photoresist layer as a etch mask.

Abstract: A stretch-deforming electrode includes a stretching portion. The stretching portion has a first stretching range and a second stretching range, in which the stretching portion has a first length variation and a first resistance variation in the first stretching range and a second length variation and a second resistance variation in the second stretching range. The first resistance variation remains substantially unchanged when the first length variation changes, the second resistance variation changes when the second length variation changes. The second resistance variation is represented by R2, the second length variation is represented by L2, and R2=A×L2, in which A is a positive number between 0.05 and 2.