Effect of temperature on the base resistance and the noise factor of a bipolar junction transistor

1972 ◽  
Vol 8 (15) ◽  
pp. 390 ◽  
Author(s):  
N.K. Shah
Keyword(s):  
Noise Factor ◽  
Effect Of Temperature ◽  
Base Resistance ◽  
Bipolar Junction Transistor ◽  
Junction Transistor

Self-aligned Process for SiC Power Devices

2010 ◽  
Vol 1246 ◽  
Author(s):  
Tomoko Borsa ◽  
Bart Van Zeghbroeck
Keyword(s):  
Electroless Plating ◽  
High Yield ◽  
Base Resistance ◽  
Power Switching ◽  
Bipolar Junction Transistor ◽  
Via Holes ◽  
Junction Transistor ◽  
Lift Off ◽  
Base Contact ◽  
Contact Metal

AbstractSilicon carbide is a semiconductor with desirable material properties, such as a wide bandgap and high thermal conductivity. It is an excellent material for constructing power switching devices operating in harsh environments where conventional semiconductors cannot adequately perform. One example of such a power device is a bipolar junction transistor (BJT). While the potential of the SiC BJT is recognized, appropriate techniques for producing devices is lacking due to its difficulty.For example, in order to achieve a high voltage 4H-SiC BJT switch with nanosecond switching time, the device must have a low base resistance. The simulation results indicate that for an emitter width of 2.0 μm and a base width of 1.2 μm the distance between the two should be 0.4 μm or less to meet the requirement for base resistance. To produce the above-described geometries and spacing, it is desirable to construct the device in a self-aligned manner. Self-alignment in this context means that the relative spacing of features of the device, such as contacts, is automatically controlled by the processing sequence and process parameters, rather than by the careful alignment prior to exposure of a photo sensitive layer. For this purpose, we developed a novel self-aligned process for SiC BJT devices, that enables the fabrication of the design with high yield, as standard silicon self-aligned technique are not applicable.The newly developed process starts with the deposition of the emitter contact metal, which provides the metal mask for the etching of the emitter ridges. Next, the wafer is planarized with photoresist and etched, so that only the emitter contacts are exposed. Electroless plating is then used to enlarge the contacts, and after removal of the resist, the plating provides an overhang, suitable for lift-off of the base contact metal. After the base contact metal deposition, the structure is planarized and etched, this time with a silicon dioxide layer, again exposing the plated emitter contacts and the lift-off step is the wet etching of the plated metal. The emitters are then all connected with a blanket wiring level, which also forms the base contact pad. This process is simpler and more robust than the process we developed to date. The main difference is the inclusion of a sacrificial lift-off overhang, created by electroless plating. It enables a well controlled overhang independent of steepness of the SiC ridge profile and the height of the emitter mesa. We successfully fabricated the overhang structure on 4H-SiC substrates.In conclusion, we report the demonstration of a new self-aligned process, which provides a self-aligned emitter contact, a self-aligned base contact and eliminates the need for via holes smaller than the emitter stripe widths. We consider this new process a major improvement over existing processes to fabricate SiC BJT devices.

scholarly journals Self-Consistent Solution of the Multi Band Boltzmann, Poisson and Hole-Continuity Equations

VLSI Design ◽  
1998 ◽  
Vol 6 (1-4) ◽  
pp. 257-260
Author(s):  
Surinder P. Singh ◽  
Neil Goldsman ◽  
Isaak D. Mayergoyz
Keyword(s):  
Boltzmann Transport Equation ◽  
The Novel ◽  
Boltzmann Transport ◽  
One Dimensional ◽  
Bipolar Junction Transistor ◽  
Continuity Equations ◽  
The Poisson Equation ◽  
Curvilinear Grid ◽  
Consistent Solution ◽  
Junction Transistor

The Boltzmann transport equation (BTE) for multiple bands is solved by the spherical harmonic approach. The distribution function is obtained for energies greater than 3 eV. The BTE is solved self consistently with the Poisson equation for a one dimensional npn bipolar junction transistor (BJT). The novel features are: the use of boundary fitted curvilinear grid, and Scharfetter Gummel type discretization of the BTE.

Nano World: A Novel Path for Modern Drug Discovery

2014 ◽  
Vol 490-491 ◽  
pp. 123-128 ◽  
Author(s):  
Nishka Ranjan ◽  
A.H. Manjunatha Reddy
Keyword(s):  
Drug Discovery ◽  
Lipid Membranes ◽  
Biological Response ◽  
Circuit Element ◽  
Bipolar Junction Transistor ◽  
Modern Drug ◽  
Pegylated Nanoparticles ◽  
Traditional Drug ◽  
Junction Transistor ◽  
Self Differentiation

The last two decades have witnessed a plethora of novel biomaterials that work significantly in the discovery of drugs and the point check of drugs, Biosensors. PLGA (Poly-(L-Lactide-co-glycolic Acid)), has already been shown to be a substrate for manufacture of substrates for OFETs, that in the future would be the forefront of electroceuticals. But, Polylactic Acid (PLA) derived and pegylated nanoparticles generated scaffolds, promote neural self-differentiation, nanowires derived from Polythiophene (PTs) can be utilised in the area of biosensors. Similarly, PT derived PEDOT:PSS(poly (3,4-ethylenedioxythiophene) poly (styrenesulfonate) polymer doped with appropriate cations is useful to manipulate directly the biological response of cells on the same grounds, organic electrochemical transistors (OECTs) based on PEDOTPSS coupled with bilayer lipid membranes (BLMs) were shown to act as ion-to-electron converters. A solid-state ion bipolar junction transistor (IBJT) has been developed to serve as a circuit element for neurotransmitter signal delivery. Consequently, the traditional drug discovery methods have far gone by. This era demands a much more modified and multiple disciplined methods for modern drug discovery. This review gives an insight and instance of this paradigm.

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