| 摘要 |
1494905 Semi-conductor device manufacture SILEC-SEMI-CONDUCTEURS 28 Nov 1974 [28 Nov 1973] 51683/74 Heading H1K In the manufacture of a Zener or avalanche breakdown diode involving sequentially coating a semi-conductor substrate with a layer of heavily doped semi-conductor material and at least one layer of metallization all the layers are deposited by ionic sputtering of target materials in a vacuum which is maintained during and between formation of the individual layers. As described 200 ohm cm. P-type silicon wafers are cleared as by etching followed by washing in aqueous and organic solvents and introduced into a sputtering apparatus the details of which are described with reference to Figs. 3 and 4 (not shown). Then with the wafers heated to above 400‹ C. adsorbed impurities are removed by bombardment with an argon ion beam first from the targets and then from the wafers to provide a dislocation free surface. The wafers are then raised to 900‹ C. and an N + layer 1000-1500 Š thick deposited thereon by directing the beam on an arsenic or antimony-doped silicon target. With the wafers at room temperature the beam is directed successively on molybdenum and nickel targets to form layers of molybdenum and nickel respectively 1000 A and 2 Á thick and optionally an intermediate layer of graded composition. After inverting the wafers automatically, or after breaking the vacuum, manually a P + layer of boron-doped silicon and contact layers of molybdenum and nickel are deposited similarly on their back faces. |
