| 摘要 |
PURPOSE:To make a junction capacitance CCB between collector and base of a semiconductor small enough and reduce the delay time of propagation by a method wherein a p<+>-layer is formed under an insulating layer surrounding an n<+>-collector- layer of I<2>L without come in contact with the collector layer. CONSTITUTION:An n epitaxial layer 2 is formed on a p-type Si substrate 1 buried with n<+>-layers 20, 21, an Si3N4 mask 22 is put on an SiO2 film made on its surface and grooves 24 are etched reaching to the buried layers. After the grooves 24 are filled with SiO2, the mask 22 are curtailed and etching is performed. p<+>-layers are formed in the n-layer 2, and are covered with SiO2 films 24'. Ion implantation is performed against a region surrounded with the p<+>-layer 25, a p-layer 26 is formed leaving the surface part and a p-layer 8 is formed in the same way being contact with a p<+>-layer 6. Openings are made selectively to form n<+>-layers 7, 27 and 30, and electrodes are formed selectively. By this constitution, p<+>n<+>-junction constituted by direct touch of layers 7 and 6 does not exist, a great junction capacitance CCB is avoided and the propagation time is shortened. Moreover the generation of crystal defect originated from p<+>n<+>-junction is avoided, and the noise is reduced. |
