Electrical, Optical, and Structural Properties of Silicon n+-p Structures

The article investigates the structural, optical, and electrical properties of silicon n+-p structures. The experimental samples were made from high-resistance single-crystal silicon using two-stage phosphorus diffusion from solid-state planar sources. It was found that the introduction of phosphorus impurities with a concentration of 1.2∙1020 cm-3 provokes the formation of dislocations with a surface density of 2∙103-3∙103 cm-2 due to the formation and relaxation of mechanical stresses. The formation of a lightening oxide film on the silicon surface reduces the reflection coefficient by 25%. However, the formation of an n+-layer reduces the transmittance coefficient of the structure. It was established from the voltage-current characteristics of the n+-p structure under forward and reverse voltage bias, that in the temperature range T = 295–346 K, these structures have rectifying properties. At room temperature, the height of the potential barrier is 0.6 eV and decreases with temperature and its height at 0 K is 1.32 еV. At low forward biases, the dominant mechanism of current transport in the structure is superbarrier emission. With an increase in forward voltage from 0.1 V to 0.6 V, the generation-recombination mechanism prevails, and with an increase in temperature, an increase in the contribution of tunnel current is observed. At low reverse voltages, the I-V characteristics of diodes are well described by the formula for the generation current. The depth of occurrence of donor energy levels, from which thermal generation of charge carriers occurs is 0.15 eV.