Maximum Fields for Nonequilibrium Suppression

The upper limit of operation of nonequihbrium devices is set by the effects of hot carriers— naturally, under the assumption that the effects of Joule heating is controlled by proper heat sinks and by structures with high-thermal conductivity. 

3 Charge Carrier Management (Thermal Noise Engineering) 

Since carrier heating caused by strong fields is antagonistic to the nonequiUb-rium depletion of the active region, and both processes are proportional to applied fields, in some point their action will become equal and remove the benefits of Auger processes. Besides that, since the main mechanism of nonradiative carrier generation is impact ionization, there is a danger of irreversible breakdown and device destmction. 

We will assume that the temperature in the expressions for Auger generation and recombination (as given in Sects. 1.4.2 and 1.4.6) actually represents carrier temperature. The increase of external fields above the hmit of hot carrier effects means an increase of Auger generation. At the same time expressions for it as quoted in Sect. 1.4 cease to be valid. 

One of the approaches to estimate the effects of scattering mechanisms is to consider carrier temperature increase due to a particular mechanism [340]. In narrow-bandgap materials for a temperature range between 200 K and room temperature the prevaihng mechanism is polar optical phonon scattering [13]. The increase of carrier temperature due to this mechanism is [341] 

---