| 摘要 |
1,110,321. Semi-conductor devices. SIEMENS A.G. 20 July, 1965 [21 July, 1964], No. 30765/65. Heading H1K. A semi-conductor device is made by forming a mesa in the surface of a sem-conductor body of one conductivity type, providing an oxide layer on the flanks of the mesa and then diffusing an impurity down the mesa to form an oxide protected PN junction. In a typical transistor of this type, Fig. 8, the me a is defined by a moat 24, the emitter zone 20 and contact 21 are linear and the base contact 22 U-shaped. Such a transistor is conveniently made by etching to form the mesa in an N- type silicon wafer, oxidizing or depositing oxide on at least the flanks of the mesa and then diffusing boron into the mesa face to form the collector junction. Subsequently, phosphorus is diffused through an aperture in oxide masking to form the emitter zone and emitter and base electrodes 21, 22 and collector electrode 15 formed by alloying aluminium and goldantimony respectively to the wafer. In forming a diode contacts are made to the bulk of the wafer and to the first diffused region. The oxide coating may be formed by evaporation, pyrolysis, or anodic oxidation or by oxidation during the early stages of the diffusion step. |
