EP0456825

A semiconductive structure where the relationship between the admixture concentrations is such that the number of carriers generated by an admixture of first-type conductivity and compensated by a third admixture is essentially equal to, or exceeds by no more than one order, the number of carriers generated by an admixture of second-type conductivity. In a method for controlling the conductivity of a semiconductive structure (1), the value of the current in the course of formation of the current column is established within a range where in the semiconductive structure (1) appears a periodical change of conductivity leading to the change of conductivity of the whole semiconductive structure (1) and a pulse sequence is obtained at the output of the semiconductive structure (1). For the structures (1) in which the number of carriers generated by the admixture of first-type conductivity and compensated by the third admixture exceeds by no more than one order the number of carriers generated by the admixture of second-type conductivity, it is necessary to apply an external influence to the structure (1) during the formation of the current column. At least one external influence is applied for controlling the change frequency of the conductivity within the zone of the current column of the structure (1).