| 摘要 |
1,037,699. Semi-conductor devices. CLEVITE CORPORATION. June 27, 1963 [Aug. 24, 1962], No. 25591/63. Heading H1K. In semi-conductor devices, a substrate of one conductivity type is provided on one of its major faces with a relatively low resistivity epitaxially grown layer of the same conductivity type, and is provided on its other major face with an indiffused region of the opposite conductivity type in which a further diffused region of the first conductivity type is formed. To make a planar transistor an N- substrate is lapped and polished to show two parallel major faces on to one of which a relatively thick N+ layer is grown. The other face is now oxide masked and provided with an indiffused P-type base region. The substrate may be mechanically reduced in thickness before masking. After reoxidation an emitter mask is formed and an N-type emitter region produced. Ohmic contacts are made to the two diffused regions and to the epitaxially grown region to complete the device. To make a mesa transistor an N+ region is grown on one face of an N- substrate and a P-type layer is formed by diffusion over the entire opposite surface of the substrate. This layer is oxide masked and an N-type emitter region formed. This region and part of the P-type base layer are masked and the remainder of the P-type layer removed to leave the mesa. Ohmic contacts are provided to the diffused regions and to the epitaxially grown layer. The Specification states that PNP devices may also be made. |
