Method for fabricating integrated circuits

A method for fabricating integrated circuits comprising the steps of:

• forming a first semiconductor growth layer on a semiconductor single-crystal substrate by chemical vapor deposition using a mixture gas of semiconductor chloride and hydrogen;
• selectively etching the first semiconductor growth layer to form therein a concave portion having bottom and side faces;
• forming an insulating film on at least one side face of the concave portion;
• forming a second semiconductor growth layer on the bottom face of the concave portion, the second semiconductor growth layer being separated from the first semiconductor growth layer by said insulating film and the top surface of the second semiconductor growth layer being at the same level as the top surface of the first semiconductor growth layer;
• and
• fabricating semiconductor devices in said substrate and first and second growth layers.

A method for fabricating integrated circuits comprising the steps of:

• forming a concave portion having bottom and side faces on a semiconductor single-crystal substrate;
• forming an insulating film on the faces of the concave portion except for at least one portion of the bottom face of the concave portion;
• forming a first semiconductor growth layer on the bottom face of the concave portion which is free of the insulating film by chemical vapor deposition using a mixture gas of semiconductor chloride and hydrogen such that the top surface of the growth layer extends a given distance above the upper surface of the substrate;
• forming a second semiconductor growth layer on the substrate such that the top surface of the second semiconductor growth layer is at the same level as the top surface of the first semiconductor growth layer;
• and
• fabricating semiconductor devices in said substrate and first and second growth layers.