PURPOSE: To restrain impurity diffusion from a low resistance region, and form a fine isolation layer, by making the isolation layer contain at least one kind of elements to restrain selectively diffusion, and then by forming a film containing conductive impurity.
CONSTITUTION: An Si3N4 film 2 is deposited on a semiconductor substrate 1, and a region, on which an isolation part is formed, is exposed by an ordinary photolithography method. Then the Si3N4 film 2 is subjected to etching. An element to restrain the transversal diffusion, for example nitrogen 3, is introduced, and P-type impurity, for example boron 4, is introduced. A resist film 5 is eliminated, and an oxide film 7 is formed by driving boron. The Si3N4 film 2 is eliminated, antimony 6, for example, is deposited, the oxide film 7 is eliminated, the antimony is driven, and a polycrystal silicon layer 8 is subjected to epitaxial growth. As nitrogen 3 is introduced in an isolation layer formed in this manner, the o diffusion from a buried layer being a low resistance region is decreased, and fine structure can be obtained.
| JP4822292 | Semiconductor device |
| WO/2022/230014 | SEMICONDUCTOR DEVICE |
MISAWA YUTAKA
SAITO RYUICHI
HITACHI HARAMACHI SEMI CONDUCT