N-type semiconductor formation principle
Both doping and defects can cause an increase in the electron concentration in the conduction band. For germanium and silicon-based semiconductor materials, doping group V elements (phosphorus, arsenic, antimony, etc.), when impurity atoms replace germanium in the lattice by substitution 1, silicon atoms can provide an extra electron in addition to satisfying covalent bond coordination, which forms an increase in the conduction band electron concentration in the semiconductor, such impurity atoms are called donors. Ⅲ-Ⅴ compound semiconductor donors are often Adopt group IV or group VI elements. Some oxide semiconductors, such as ZnO, Ta2O5, etc., the chemical ratio is often hypoxic, these oxygen vacancies can show the role of donors, so this type of oxide is usually electronic conductivity, that is It is an N-type semiconductor. Heating in vacuum can further enhance the degree of oxygen deficiency, which is manifested as stronger electronic conductivity.