Manufacture of semiconductor device

TLDR: In this paper, the N-type base layers and emitter layers are formed to the transistor forming sections, the periphery thereof are surronded by insulating isolating oxide films, extracting electrodes are formed, and the transistors of the memory cell region and the peripheral circuit region are formed.

Abstract: PURPOSE:To manufacture a large-capacitance high-speed semiconductor memory with high yield as a whole by manufacturing a transistor in a memory cell region with excellent yield and forming a transistor having high performance in a peripheral circuit region. CONSTITUTION:N Type buried layers are formed in a large number of regions as the transistor forming sections of a P type silicon substrate, and an N type silicon single crystalline layer is deposited on the surface of the substrate containing the buried layers, thus forming a composite substrate. A silicon oxide film and a silicon nitride film are formed to the surface of the substrate. Other regions are oxidized while leaving the silicon nitride film of the transistor forming sections on the buried layers in a memory cell region, and the oxide film is removed. Other regions are etched up to the depth of the silicon single crystalline layer while leaving the silicon nitride film of the transistor forming sections on the N type impurity buried layers in the peripheral circuit region except the memory cell region. Other regions in a first region and a second region are oxidized up to the P type silicon substrate. The silicon nitride film of the first region and the second region is removed through etching, P type base layers and N type emitter layers are formed to the transistor forming sections, the periphery thereof are surronded by insulating isolating oxide films, extracting electrodes are formed, and the transistors of the memory cell region and the peripheral circuit region are formed.