Measuring Mobility and Density of Charge Carriers Near a P-N Junction

Abstract

Two types of probe measurement are described which allow the determination of the conductivity mobility and the density of majority carriers in the neighborhood of p‐n junctions. The first of these measures the change in sheet conductivity of a layer as a function of the reverse bias applied to a junction bounding the layer. The second measures the capacitance of the junction vs. the reverse bias. The techniques are applied to silicon p‐n junctions of both the epitaxial and diffused variety. A significant difference is observed in the mobility variation near these two types of junction.

Microelectronic test pattern NBS-3 for evaluating the resistivity-dopant density relationship of silicon

“…This expression is similar to those derived by others [11] . The incremental region is located at a distance W from a one-sided junction.…”

“…from the tetrode transistor (3.6). With the use of methods described elsewhere [11], these two structures allow resistivity values to be determined over several decades in dopant density.…”

“…The collector resistivity, p, is calculated from [24] p = (V/I) (2us)/(2-/^) (11) where the potential, V, is V1-V2 for a current, I, passed into and out of I2 and s is the probe spacing.…”