摘要:
A heterojunction bipolar transistor having a single-crystal emitter with reduced charge storage and acceptable current gain is described herein. The heterojunction transistor comprises a collector region, a base region formed on the collector region, and a single-crystal emitter region grown on the base region by low temperature epitaxy. During the formation of the base region, a graded profile of 5-23% germanium is added to the base, as the distance to the collector region decreases, thereby decreasing the base bandgap as it approaches the collector region. Further, during the formation of the emitter region, a graded profile of 0-20% germanium is added to the emitter as the distance from the emitter-base junction increases. Thus, the emitter bandgap decreases as it moves farther from the emitter-base junction. The result of the above grading profiles is that the emitter bandgap is narrower at the emitter contact than the base bandgap at the emitter-base junction.
摘要:
A P- semiconductor material substrate which has been ion-implanted with N-type dopants to form an N+ subcollector layer is annealed in Argon to further remove implant damage and drive the dopant ions deeper into the P substrate. Next a lightly doped N- epitaxial layer is grown on the N+ subcollector layer. This forms the blanket collector. A P- well region is formed by growing a pad oxide of 10 nm on the N-epi layer and a 200 nm layer of nitride is then deposited on top of the layer oxide. A photoresist etch mask is used to pattern the P- well region. A reactive ion etch is performed through the dielectric oxide and nitride layers, through the epitaxial layer and stopping in the subcollector layer. A layer of low temperature expitaxial material is grown over the structure using ultra-high vacuum/chemical vapor depositions such that the epitaxial layer extends above the surface of the epitaxial layer and includes a P+ heavily doped layer and a lightly P-doped surface layer. The heavily doped P+ layer provides the low resistance contact to the collector region and the lightly doped P-layer is the collector region and its thickness is determined by the diffusion of the heavily doped layer during the entire process.
摘要:
A method of forming a bipolar transistor is provided, comprising the steps of: providing a semiconductor substrate including a first region of a first conductivity type; forming a layer of insulative material over a surface of the first region; forming a layer of conductive material over the layer of insulative material; patterning the first and second layers to form a generally vertical sidewall bounding an exposed portion of the first region surface; and epitaxially depositing a base region of a second conductivity type over the exposed portion of the first region surface and the sidewall such that the base region is in electrical contact with the second region.
摘要:
A complementary bipolar transistor structure having one symmetrical intrinsic region for both the NPN and PNP transistors and a method for fabricating the structure. The transistor structure includes a vertical NPN transistor operating in the upward direction and a vertical PNP transistor operating in a downward direction. In the method, the sub-emitter and the sub-collector regions are formed by depositing a first epitaxial layer of semiconductor material of a first conductivity type on the surface of a semiconductor substrate of a second conductivity type, and forming the sub-collector by etching a shallow trench in the first layer and depositing semiconductor material of a second conductivity type by LTE and planarizing. The intrinsic regions for both of the transistors are formed by depositing a second layer of semiconductor material of the second conductivity type on the surface of the first layer and a third layer of semiconductor material of the first conductivity type on the surface of the second layer by either LTE or MBE. In one embodiment, the second and third layers are provided with a uniform vertical doping profile for one thickness of the layer and a graded doping profile for the remaining thickness in which the minimum doping level for both graded portions is at the junction between the second and third layers. The second layer forms the base and the third layer forms the collector for one transistor while at the same time the second layer forms a collector and the third layer forms the base for the other transistor. The performance of the intrinsic base and collector regions can be further improved by forming the second and third layers with a compound semiconductor material, such as, the compound of Si-Ge to create a heterojunction transistor. Device and intrinsic region isolation is effected by a combination of deep trench and shallow trench processes and reach-through regions for the sub-emitter and sub-collector are formed. A layer of polysilicon is deposited and selectively etched to form an extrinsic collector region for one transistor and extrinsic base regions for the other transistor. A further layer of single crystal silicon is deposited to form the extrinsic base region for one transistor and the emitter for the other transistor.
摘要:
A method of forming a bipolar transistor is provided, comprising the steps of: providing a semiconductor substrate including a first region of a first conductivity type; forming a layer of insulative material over a surface of the first region; forming a layer of conductive material over the layer of insulative material; patterning the first and second layers to form a generally vertical sidewall bounding an exposed portion of the first region surface; and epitaxially depositing a base region of a second conductivity type over the exposed portion of the first region surface and the sidewall such that the base region is in electrical contact with the second region.
摘要:
A heterojunction bipolar transistor (HBT) may include an n-type doped crystalline collector formed in an upper portion of a crystalline silicon substrate layer; a p-type doped crystalline p+Si1-xGex layer, formed above the n-type doped collector, that forms a p-type doped internal base of the HBT; a crystalline silicon cap formed on the p-type doped crystalline p+Si1-xGex layer, in which the crystalline silicon cap includes an n-type impurity and forms an n-type doped emitter of the HBT; and an n-type doped crystalline silicon emitter stack formed within an opening through an insulating layer to an upper surface of the crystalline silicon cap.
摘要:
Lateral PNP bipolar junction transistors, methods for fabricating lateral PNP bipolar junction transistors, and design structures for a lateral PNP bipolar junction transistor. An emitter and a collector of the lateral PNP bipolar junction transistor are comprised of p-type semiconductor material that is formed by a selective epitaxial growth process. The source and drain each directly contact a top surface of a device region used to form the emitter and collector. A base contact may be formed on the top surface and overlies an n-type base defined within the device region. The emitter is laterally separated from the collector by the base contact. Another base contact may be formed in the device region that is separated from the other base contact by the base.
摘要:
Aspects of the invention provide for a bipolar transistor of a self-aligned emitter. In one embodiment, the invention provides a method of forming local wiring for a bipolar transistor with a self-aligned sacrificial emitter, including: performing an etch to remove the sacrificial emitter to form an emitter opening between two nitride spacers; depositing an in-situ doped emitter into the emitter opening; performing a recess etch to partially remove a portion of the in-situ doped emitter; depositing a silicon dioxide layer over the recessed in-situ doped emitter; planarizing the silicon dioxide layer via chemical mechanical polishing; etching an emitter trench over the recessed in-situ doped emitter; and depositing tungsten and forming a tungsten wiring within the emitter trench via chemical mechanical polishing.
摘要:
Bulk acoustic wave filters and/or bulk acoustic resonators integrated with CMOS devices, methods of manufacture and design structure are provided. The method includes forming a single crystalline beam from a silicon layer on an insulator. The method includes providing a coating of insulator material over the single crystalline beam. The method further includes forming a via through the insulator material. The method further includes providing a sacrificial material in the via and over the insulator material. The method further includes providing a lid on the sacrificial material. The method further includes providing further sacrificial material in a trench of a lower wafer. The method further includes bonding the lower wafer to the insulator, under the single crystalline beam. The method further includes venting the sacrificial material and the further sacrificial material to form an upper cavity above the single crystalline beam and a lower cavity, below the single crystalline beam.
摘要:
Disclosed are embodiments of a bipolar or heterojunction bipolar transistor and a method of forming the transistor. The transistor can incorporate a dielectric layer sandwiched between an intrinsic base layer and a raised extrinsic base layer to reduce collector-base capacitance Ccb, a sidewall-defined conductive strap for an intrinsic base layer to extrinsic base layer link-up region to reduce base resistance Rb and a dielectric spacer between the extrinsic base layer and an emitter layer to reduce base-emitter Cbe capacitance. The method allows for self-aligning of the emitter to base regions and incorporates the use of a sacrificial dielectric layer, which must be thick enough to withstand etch and cleaning processes and still remain intact to function as an etch stop layer when the conductive strap is subsequently formed. A chemically enhanced high pressure, low temperature oxidation (HIPOX) process can be used to form such a sacrificial dielectric layer.