Semiconductor circuit structure and method for making the same

A method of producing a semiconductor circuit structure comprising the steps of:

• providing a first semiconductor substrate layer and a second semiconductor substrate layer;
• forming a concave portion on a main surface of said second semiconductor substrate layer;
• forming a groove extending from a bottom of said concave portion into said second semiconductor substrate layer, said groove having a depth measured from the main surface of said second semiconductor layer deeper than the depth of said concave portion, and said groove extending laterally in said second semiconductor layer to open on a side wall of said semiconductor substrate layer for introducing oxygen gas thereinto;
• forming a semiconductor substrate portion by directly connecting said main surface of said second semiconductor substrate layer to a main surface of said first semiconductor substrate layer to form a vacant portion defined between a bottom surface of said concave portion and the main surface of said first semiconductor substrate layer;
• filling at least said vacant portion with an oxidized material to form a buried layer serving as an insulating layer and forming an oxide film at least on an inside wall of said groove, and
• removing a part of the semiconductor substrate layer in which said groove is provided, from a free end surface thereof, to uncover a portion of said groove and to form a region insulatedly isolated from other regions by a film-shaped material formed of said buried layer formed in said second semiconductor substrate.

A method of producing a semiconductor circuit structure comprising the steps of:

• providing a first semiconductor substrate layer and a second semiconductor substrate layer;
• forming a concave portion on a main surface of said first semiconductor substrate layer;
• forming a projecting portion on a main surface of said second semiconductor substrate layer having a height less than the depth of said concave portion, and said projecting portion having a configuration such that it can be inserted into said concave portion;
• forming a groove along a boundary portion of said projecting portion in said second semiconductor substrate layer and extending thereinto;
• forming a semiconductor substrate portion by directly connecting said first and said second semiconductor substrate layer so that said projecting portion is inserted into said concave portion to form a vacant portion defined by the bottom surface of said concave portion and a top surface of said projecting portion;
• filling at least said vacant portion with an oxidized material to form a buried layer serving as an insulating layer and forming an oxide film at least on an inside wall of said groove, and
• removing a part of said second semiconductor substrate layer from a free end surface thereof to uncover said main surface of said first semiconductor substrate layer outside of said concave region to form a region made of said second semiconductor substrate layer insulatedly isolated from other regions made of said first semiconductor substrate layer by a film-shaped portion including said buried layer formed in said first semiconductor substrate.