Denso Corporation

Sumco Corporation

Nobuhiro Tsuji

Shoichi Yamauchi

Hitoshi Yamaguchi

Toshiyuki Morishita

Tomonori Yamaoka

Syouji Nogami

Yasushi Urakami

Toshio Sakakibara

Jun Sakakibara

A semiconductor substrate is provided in which an alignment mark is formed that can be used for an alignment even after the formation of an impurity diffused layer by the planarization of an epitaxial film. A trench is formed in an alignment region of an N-type layer formed on an N-type substrate. This trench is used to leave voids after the formation of a P-type epitaxial film on the N-type layer. Then, the voids formed in the N-type layer can be used as an alignment mark. Thus, such a semiconductor substrate can be used to provide an alignment in the subsequent step of manufacturing the semiconductor apparatus. Thus, the respective components constituting the semiconductor apparatus can be formed at desired positions accurately.

Method for manufacturing semiconductor substrate

A semiconductor substrate is provided in which an alignment mark is formed that can be used for an alignment even after the formation of an impurity diffused layer by the planarization of an epitaxial film. A trench is formed in an alignment region of an N-type substrate. This trench is used to leave voids after the formation of an N-type layer. Then, the voids formed in the N-type substrate can be used as an alignment mark. Thus, such a semiconductor substrate can be used to provide an alignment in the subsequent step of manufacturing the semiconductor apparatus. Thus, the respective components constituting the semiconductor apparatus can be formed at desired positions accurately.

A trench is formed in a semiconductor substrate through a mask composed of a silicon oxide film formed on the semiconductor substrate. Then, an edge portion at an opening portion of the mask is etched so that the width of the mask opening width is greater than the width of the trench. After that, the inner surface of the trench is smoothed by thermal treatment around at 1000&#xb0; C. in non-oxidizing or non-nitriding atmosphere under low pressure. Then, the trench is filled with an epitaxial film. After that, the epitaxial film is polished to complete the substrate.

Semiconductor substrate formed by epitaxially filling a trench in a semiconductor substrate with a semiconductor material after smoothing the surface and rounding the corners

In a method for manufacturing a semiconductor device of the present invention, a portion of a first epitaxial layer formed in a trench in a silicon substrate is removed by vapor phase etching using a halogenated compound or hydrogen. In this removing process, the portion of the first epitaxial layer is removed at a predetermined temperature higher than that during epitaxial growth of the first epitaxial layer and at a predetermined pressure higher than that during epitaxial growth of the first epitaxial layer. Therefore, stress that would otherwise be concentrated at a bottom portion of the trench is relaxed because rearrangement of the silicon atoms increases.

Method for manufacturing semiconductor device with semiconductor region inserted into trench

A semiconductor device includes a semiconductor substrate and a semiconductor layer. The semiconductor substrate has a main surface that is an Si&lcub;100&rcub; surface. The substrate has a trench in the main surface. The semiconductor layer is located on surfaces defining the trench to have common crystallographic planes with the semiconductor substrate. The trench is defined by a bottom surface, two long sidewall surfaces that face each other, and two short sidewall surfaces that face each other. The bottom surface and the long sidewall surfaces are Si&lcub;100&rcub; surfaces.

Semiconductor device having epitaxially-filled trench and method for manufacturing semiconductor device having epitaxially-filled trench

A trench is formed in a semiconductor substrate through a mask composed of a silicon oxide film formed on the semiconductor substrate. Then, an edge portion at an opening portion of the mask is etched so that an opening width thereof is wider than that of the trench. After that, an inner surface of the trench is smoothed by thermal treatment around at 1000&deg; C. in non-oxidizing or non-nitriding atmosphere under low pressure. Then, the trench is filled with an epitaxial film. After that, the epitaxial film is polished, whereby a semiconductor substrate for forming a semiconductor device is obtained.

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Kariya, Japan

Nobuhiro Tsuji