Effect of emitter diffusion parameters on device characteristics

This paper describes the effect of emitter surface concentration and emitter depth on the temperature coefficient of collector current, band gap narrowing in the emitter region, and burst noise characteristics of NPN transistors. A group of transistors were fabricated with three different surface concentrations /cm³ /cm³and /cm³) with a fixed emitter depth of XJE= 1.5 µm. A second group of transistors were fabricated with three different emitter depths (XJE= .8µm, 1.5µm and 2.2µm) and fixed surface concentration ( /cm³). Few units from each group were subjected to an annealing experiment where the devices were heated to 800°C for 16 hours in a nitrogen atmosphere.