Exact analysis of current hogging effect in microwave power transistor

In microwave power transistors one of the most serious short-term failure modes is due to what is known as "Current-Hogging" effect. The emitter ballasting is the most effective way of minimizing this problem and is being practiced widely today. However, since the exact account of this effect requires a complex three dimensional thermal analysis coupled with minority carrier injection mechanism, which in turn is dependent on the external circuit, complete analysis of this phenomenon has not been carried out thus far.