SEMICONDUCTOR DEVICE

摘要

1485654 Semi-conductor devices ITT INDUSTRIES Inc 11 Nov 1975 [15 Nov 1974] 46521/75 Heading H1K Electrical insulation regions 50 or 76 of an anodized metal, in particular aluminium, are provided in a semi-conductor body by depositing the metal 44 (Fig. 4), on a dielectric layer 40 and in grooves (42), formed in the body, the thickness of the metal layer 44 being such that the metal layer in the dielectric layer and those in the grooves are not in contact with each other, and then anodizing the metal layers 44 in the grooves. The thickness of the vapour deposited aluminium is preferably 2/3 the thickness of an N-type epitaxial layer 34 having graded impurity concentration, and the anodic oxidation of the entire aluminium layer in the groove is carried out by immersing the semiconductor body in chromic, sulphuric, phosphoric or oxalic acid, the aluminium layer in the groove acting as anode, whereby on complete anodization aluminium increases in volume by 1À5 times and completely fills the groove. The aluminium layer may not be completely anodized in which case shorting between spaced apart portions of the epitaxial layer by the unanodized aluminium 68 is prevented by the formation of oxidized layers 66 along the walls of the grooves, Fig. 20, prior to the deposition of the metal, the unanodized metal layer subsequently acting as an electrical conductor for the entire integrated circuit formed in the semiconductor body. Base region, emitter region and collector contact region 58, 60, and 62 respectively, are diffused in each isolated epitaxial layer portion either before or after the anodization of aluminium using known photoresist techniques. P-type impurity may be diffused in the walls of the grooves prior to the formation of oxidized layers 66 to form P-type regions in the N-type epitaxial sub-layer (38), Fig. 3 (not shown) and the P-type substrate 30, but not in the highly doped N+ epitaxial sublayer (36). Encapsulation of the integrated circuit with individual external connections for the emitter, base and collector regions is described, Fig. 9 (not shown).