| 摘要 |
1290318 Semi-conductor devices SIEMENS AG 8 July 1970 [9 July 1969] 33089/70 Heading HIK A PNP germanium planar transistor comprises diffused base and emitter regions, the donor diffused region being formed from a donor doped SiO 2 layer masked by a pure SiO 2 layer on the wafer surface, the doped SiO 2 layer itself acting as a mask for an acceptor diffusion. In a method of manufacturing the device, the pure SiO 2 layer 2 is thermally deposited on a wafer 1 and etched to form a window. A donor doped SiO 2 layer 4 is deposited over layer 2 and the window, and diffusion carried out to form a preliminary base zone. A second window 8 is formed in the layer 4 and an acceptor impurity diffused through the window 8 to form an emitter region. During emitter diffusion the layer 4 acts as a mask to the acceptor impurity, and further donor diffusion also takes place to form the final base zone 6. Contacts to the emitter zone may be of gold/gallium or silver/ gallium, and to the base zone of gold/antimony and/or silver/antimony. Initial contacts may be covered with a chromium and silver layer, or a chromium and a silver layer only may be used. Dopants may be of gallium and phosphorus with the wafer containing an indium impurity. |
