Method of manufacturing semiconductor device

Claim 1

A method of manufacturing a semi-conductor device comprising a bipolar transistor operated with a carrier of a first conductivity type used as a majority carrier and a MOS transistor operated with a carrier of a second conductivity type used as a majority carrier, wherein said semiconductor device further comprises: a first step of forming a first impurity implanted layer of the first conductivity type forming a first buried layer in a bipolar transistor forming region on a main surface of a semiconductor substrate of the second conductivity type and forming a second impurity implanted layer of the first conductivity type forming a second buried layer in a MOS transistor forming region, said second impurity implanted layer being separated from said first impurity implanted layer, and then, forming an epitaxial growth layer of the first conductivity type on said semiconductor substrate under a condition that said first and second buried layers are not in contact with each other; a second step of forming, in a boundary between said bipolar transistor forming region and said MOS transistor forming region, a trench having a depth larger than a lower end of said first buried layer of the first conductivity type formed in said bipolar transistor forming region; a third step of burying said trench with a buried film for insulating; a fourth step of forming a well layer of the first conductivity type by implanting, at high energy, an impurity of the first conductivity type into a region including at least said epitaxial growth layer in said MOS transistor forming region after said third step has been performed; a fifth step of forming a gate electrode, a gate insulating film and source/drain diffusion layers in said MOS transistor forming region; and a sixth step of forming an emitter diffusion layer, a base diffusion layer and a collector diffusion layer in said bipolar transistor forming region.

Claim 2

A method of manufacturing a semi-conductor device comprising a bipolar transistor operated with a carrier of a first conductivity type used as a majority carrier and a MOS transistor operated with a carrier of a second conductivity type used as a majority carrier, wherein said semiconductor device further comprises: a first step of forming a first impurity implanted layer of the first conductivity type forming a first buried layer in a bipolar transistor forming region on a main surface of a semiconductor substrate of the second conductivity type and forming a second impurity implanted layer of the first conductivity type forming a second buried layer in a MOS transistor forming region, said second impurity implanted layer being separated from said first impurity implanted layer, and then, forming an epitaxial growth layer of the first conductivity type on said semiconductor substrate under a condition that said first and second buried layers are not in contact with each other; a second step of forming, in a boundary between said bipolar transistor forming region and said MOS transistor forming region, a trench having a depth larger than a lower end of said first buried layer of the first conductivity type formed in said bipolar transistor forming region; a third step of burying said trench with a buried film for insulating; a fourth step of forming a well layer of the first conductivity type by implanting, at high energy, an impurity of the first conductivity type into a region including at least said epitaxial growth layer in said MOS transistor forming region after said third step has been performed; a fifth step of forming a gate electrode, a gate insulating film and source/drain diffusion layers in said MOS transistor forming region; and a sixth step of forming an emitter diffusion layer, a base diffusion layer and a collector diffusion layer in said bipolar transistor forming region.

Claim 6

A method of manufacturing a semiconductor device comprising: a first step of forming a trench on a main surface of a semiconductor substrate; a second step of depositing a buried film of polycrystal including plural crystal grains on the entire surface of said semiconductor substrate after said first step has been performed; a third step of conducting a heat treatment for changing said crystal grains of said buried film into large crystal grains with said buried film deposited on the entire surface of said semiconductor substrate after said second step has been performed; and a fourth step of allowing said buried film to remain in said trench by etching back said buried film after said third step has been performed.

Claim 7

A method of manufacturing a semiconductor device comprising: a first step of forming a trench on a main surface of a semiconductor substrate; a second step of depositing a buried film of polycrystal including plural crystal grains on the entire surface of said semiconductor substrate after said first step has been performed; a third step of conducting a heat treatment for changing said crystal grains of said buried film into large crystal grains with said buried film deposited on the entire surface of said semiconductor substrate after said second step has been performed; and a fourth step of allowing said buried film to remain in said trench by etching back said buried film after said third step has been performed.