Solid-state imaging device and method of manufacturing the same
An n/p − /p + substrate where a p − -type epitaxial layer and an n-type epitaxial layer have been deposited on a p + -type substrate is provided. In the surface region of the n-type epitaxial layer, the n-type region of a photoelectric conversion part has been formed. Furthermore, a barrier layer composed of a p-type semiconductor region has been formed so as to enclose the n-type region of the photoelectric conversion part in a plane and reach the p − -type epitaxial layer from the substrate surface. A p-type semiconductor region has also been formed at a chip cutting part for dividing the substrate into individual devices so as to reach the p − -type epitaxial layer from the substrate surface.
1. A solid-state imaging device comprising:
a semiconductor substrate which includes p-type impurities;
a p-type epitaxial layer which is formed on the semiconductor substrate and includes p-type impurities whose concentration is lower than that of the semiconductor substrate;
an n-type epitaxial layer which includes n-type impurities formed on the p-type epitaxial layer;
a plurality of photoelectric conversion parts which are included n-type regions provided at the surface region of the n-type epitaxial layer;
a plurality of element isolating regions which are formed in the n-type epitaxial layer to enclose each of said plurality of photoelectric conversion parts in a plane and each of which includes a first p-type semiconductor layer that is formed to reach the p-type epitaxial layer from the surface region of the n-type epitaxial layer and isolates said plurality of photoelectric conversion parts from one another; and
a chip cutting part dividing an element-formed semiconductor substrate into chips and that includes an element isolation insulating film formed at the surface region of the n-type epitaxial layer and a second p-type semiconductor layer formed to reach the p-type epitaxial layer from the surface region of the n-type epitaxial layer along the region where the element isolation insulating film is formed.
2. The solid-state imaging device according to claim 1 , wherein each of the element isolating regions includes an element isolation insulating film formed at the surface region of the n-type epitaxial layer in the upper part of the first p-type semiconductor layer.
3. The solid-state imaging device according to claim 2 , wherein the element isolation insulating film is filled in a trench formed in the surface region of the n-type epitaxial layer.
4. The solid-state imaging device according to claim 1 , wherein the first p-type semiconductor layer includes a plurality of semiconductor layers each formed in a different position in the depth direction of the substrate.
5. The solid-state imaging device according to claim 1 , wherein the p-type impurities included in the semiconductor substrate and the p-type epitaxial layer are boron and the n-type impurities included in the n-type epitaxial layer are phosphorous and the first p-type semiconductor layer includes boron as p-type impurities.
6. The solid-state imaging device according to claim 5 , wherein the p-type impurities included in the p-type epitaxial layer and those included in the first p-type semiconductor layer have the same impurity concentration.
7. The solid-state imaging device according to claim 1 , wherein the second p-type semiconductor layer includes a plurality of semiconductor layers each formed in a different position in the depth direction of the substrate.
8. The solid-state imaging device according to claim 1 , wherein the p-type impurities included in the semiconductor substrate and the p-type epitaxial layer are boron and the n-type impurities included in the n-type epitaxial layer are phosphorous and the first and second p-type semiconductor layers include boron as p-type impurities.
9. The solid-state imaging device according to claim 1 , further comprising a shield layer which includes p-type impurities formed at the surface region of each of said plurality of photoelectric conversion parts.