Active solid-state devices (e.g. – transistors – solid-state diode – With groove to define plural diodes
Reexamination Certificate
1999-11-09
2001-10-16
Munson, Gene M. (Department: 2811)
Active solid-state devices (e.g., transistors, solid-state diode
With groove to define plural diodes
C257S051000, C257S910000
Reexamination Certificate
active
06303975
ABSTRACT:
BACKGROUND OF THE INVENTION
Solid state diodes are used in a variety of circuit applications operating in the radio frequency range. Specifically, pin diodes and varactor diodes are used for switching purposes, as well as circuit tuning components in circuits which operate in the microwave frequency range. Varactor diodes are, for instance, commonly used to implement a voltage controlled tuning function, such as the setting of the frequency of a voltage controlled oscillator.
One of the component characteristics which limits the performance of varactor diodes and pin diodes is the series resistance which the diode offers to a radio frequency signal. In the case of a varactor diode, the Q established by a resonant circuit using the diode is highly dependent upon the series resistance of the varactor diode. In pin diode applications, the power loss incurred when switching RF signals is a significant function of the series resistance of the pin diode when biased into the conducting mode.
The series resistance of these devices in a silicided polysilicon base bipolar transistor technology is a function of the current flow from the edges of the diode active area toward the center of the diode. In the prior art approach for implementing a varactor diode or pin diode, narrow fingers of active base-collector areas, interspersed with cathode contacts on either side, are implemented in a base collector region of a silicided polysilicon base transistor. The long narrow fingers of active base collector area provide scalable area, and a relatively low series resistance since the width of the active region is kept as small as possible. However, the long, narrow diode fingers present a series resistance which is not at a minimum. It has been determined that the minimum series resistance is obtained when the perimeter to area ratio of the base collector region is minimized, and the long fingers increase the resistance associated with the diode active region. The series resistance down the length of the anode and cathode contacts also cause current crowding along the length, contributing to the resistance of the device. Accordingly, the present invention is directed to a high frequency diode which has been designed to have a minimum series resistance.
SUMMARY OF THE INVENTION
A low noise, high frequency solid state diode is provided which includes a matrix of diode cell units. Each of the diode cell units includes a polysilicon base region forming an active diode, having an anode and a cathode region. A subcollector is formed below the cathode region of each of the cell units, which overlap the subcollectors of adjacent cell units of the matrix, forming a continuous subcollector. A uniform array of contacts are provided on the surface of the matrix of diode cell units in contact with the subcollector region, and a second array of contacts are connected to each base region of each of the cell units. By interconnecting all of the first set of subcontacts in parallel, and all of the second set of contacts in parallel, the matrix of diode cell units are connected in parallel producing a single diode having a low series resistance.
In accordance with the present invention, each of the cell units has an active base region which has a minimum perimeter to area ratio shared common subcollector among the diode cell units for reducing the series resistance for the diode formed by the matrix of cell units.
REFERENCES:
patent: 3878553 (1975-04-01), Sirles et al.
patent: 4331887 (1982-05-01), Jadus et al.
patent: 5099299 (1992-03-01), Fang
patent: 5107233 (1992-04-01), Stoft
patent: 5153453 (1992-10-01), Walters
patent: 5318916 (1994-06-01), Enquist et al.
patent: 5446294 (1995-08-01), Bayraktaroglu
patent: 5471078 (1995-11-01), Bayraktaroglu
patent: 5508552 (1996-04-01), Iranmanesh et al.
patent: 5554924 (1996-09-01), McMahon et al.
patent: 5561306 (1996-10-01), Imamura et al.
patent: 5572063 (1996-11-01), Iranmanesh et al.
patent: 5587327 (1996-12-01), König et al.
patent: 5648278 (1997-07-01), Bayraktaroglu
patent: 5656514 (1997-08-01), Ahlgren et al.
patent: 5821820 (1998-10-01), Snider et al.
patent: 5854102 (1998-12-01), Gonzalez et al.
Groves Robert A.
Jadus Dale K.
Nguyen-Ngoc Dominique
Walter Keith M.
Connolly Bove Lodge & Hutz
International Business Machines - Corporation
Munson Gene M.
LandOfFree
Low noise, high frequency solid state diode does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Low noise, high frequency solid state diode, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Low noise, high frequency solid state diode will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2609494