PURPOSE: To shorten data reading and writing times and to obtain large-capacity, high-speed bipolar memories, by enlarging the thickness of an epitaxial layer, in which a memory-cell peripheral circuit is formed, and securing the effective thickness of the (p) epitaxial layer to some extent even after impurities from an n+ embedded layer rise up.
CONSTITUTION: An impurity introduced mask is formed on one main surface of a p- type semiconductor substrate 3. Ions of boron and arsenic As are selectively implanted in the p- type semiconductor substrate 3. Then an epitaxial layer 6 is formed on the main surface of the semiconductor substrate 3. The impurities introduced in the semiconductor substrate 3 are diffused by heat applied at this time, and a p+ layer 5 and an n+ embedded layer 4 are formed. A surface oxide film 14 and a part of the epitaxial layer 6 are selectively etched. Then a groove is formed in an isolation forming region. This part is selectively oxidized, and a thick oxide film 7 is formed. The isolation region is formed by the oxide film 7 and the p+ diffused layer 5. Thereafter, impurity diffused layers 8∼13 are selectively formed on the main surface of the epitaxial layer 6 by using ordinary technology.
| JPH0529329 | MANUFACTURE OF SEMICONDUCTOR DEVICE |
YAMAZAKI KAZUO
GOTOU NOBUYUKI
UCHIDA HIDEAKI
