08-16-2017, 09:19 PM
construction and working of impatt diode pdf
Abstract
In many respects, the IMPATT diode structure is very similar to that of many other forms of diode, and in particular the standard PN junction diode or the Schottky diode.However the differences in its construction and fabrication mean that it is able to operate in its avalanche mode whether the transit time provides the negative resistance.
There is a variety of structures that are used for the IMPATT diode. All are variations of a basic PN junction and usually there is an intrinsic layer, i.e. a layer without any doping that is placed between the P type and N type regions.The structures use a PN junction which is reverse biased so that avalanche multiplication occurs within the high field region. In most structures a Schottky barrier can be used as the injecting junction.
Introduction
An IMPATT diode (IMPact ionization Avalanche Transit-Time diode) is a form of high-power semiconductor diode used in high-frequency microwave electronics devices. They have negative resistance and are used as oscillators to generate microwaves as well as amplifiers. They operate at frequencies between about 3 and 100 GHz or more. A main advantage is their high-power capability. These diodes are used in a variety of applications from low-power radar systems to proximity alarms. A major drawback of using IMPATT diodes is the high level of phase noise they generate. This results from the statistical nature of the avalanche process.