Halbleiteranordnung

Semi-conductor Device

... 1,188,688. Semi-conductor devices. ALLMANNA SVENSKA ELEKTRISKA A.B. 27 June, 1967 [28 June, 1966], No. 29552/67. Heading H1K. The PN junction 1 between regions 3 and 8 of a semi-conductor body is formed by diffusion of suitable impurity into a plane surface 2 of the body under such conditions that the angle between the junction 1 and the surface 2 is less than 45 degrees and preferably within the range 1 to 10 degrees. The junction may be the sole junction of a diode or, as shown, the centre junction of a PNPN thyristor. To achieve the required value for the angle , the surface 2 is covered before diffusion with a layer of a substance in which the diffusion rate is at most of the same order as the rate of diffusion in the semi-conductor, e.g. in the case of silicon as semi-conductor a layer of silicon dioxide or nitride or carbide. This layer is thin or non-existent at the centre of the surface 2 and of progressively increasing thickness towards the edge. When impurity is diffused through ...