Doping Profile Meter for Semiconductor Structures

A measuring device designed to gauge the distribution of electrically charged impurities within strongly asymmetric p - n junctions, Schottky barriers, and metal - insulator - semiconductor structures, employs the capacitance - voltage method. This device is controlled by a personal computer through a microcontroller. The coordinates of the concentration profile points are determined through a simultaneous selection of signals proportional to the concentration and its spatial coordinate, achieved by the selective hardware separation of information frequencies from a polyharmonic voltage. This process occurs in a structure installed in the negative-feedback circuit of the operational amplifier. The entire profiling process takes 30 seconds. It boasts a depth resolution of 15 angstroms (equivalent to 3-4 atomic layers of the crystal lattice) at an impurity concentration of 5 x 1017 cm-3, with a maximum measured concentration of 5 x 1018 cm-3. The dimensions of the measuring device are 180 x 120 x 50 mm. The study presents examples of its practical applications.