Method for the epitaxial manufacture of a semiconductor device having a multi-layer structure

Claim 1

A method for epitaxial manufacture of semiconductor devices having a multilayer structure consisting of a base semiconductor substrate extending to an upper active surface with a p-n junction in proximity thereto comprising the steps of forming an epitaxial connection layer on said substrate having a chemical composition substantially identical to said substrate, forming a plurality of successive epitaxial intermediate layers on said connection layer, said intermediate layers being chemically formed by elements of said substrate with at least one additional complementary element, said complementary element in each intermediate layer substantially increasing in amount in each intermediate layer in proportion to distance from said substrate, said substrate having crystal lattice dimensions smaller than those of said intermediate layers, and forming at least one semiconductor layer on said intermediate layers, said semiconductor layer being chemically formed by elements of said substrate with at least one additional complementary element, said substrate having crystal lattice dimensions smaller than those of said semiconductor layer, wherein the relative increase of said crystal lattice dimensions of a first intermediate layer in closest proximity to said substrate is chosen to be less than 1.2×10 -3 relative to the crystal lattice dimensions of said substrate, and wherein the relative increase of the crystal lattice dimensions a n of the n th intermediate layer to the crystal lattice dimensions a n-1 of the n-1 intermediate layer is chosen to be equal to αn where α is a coefficient between 6×10 -4 and 1.6×10 -3 .

Claim 2

A method for epitaxial manufacture of semiconductor devices having a multilayer structure consisting of a base semiconductor substrate extending to an upper active surface with a p-n junction in proximity thereto comprising the steps of forming an epitaxial connection layer on said substrate having a chemical composition substantially identical to said substrate, forming a plurality of successive epitaxial intermediate layers on said connection layer, said intermediate layers being chemically formed by elements of said substrate with at least one additional complementary element, said complementary element in each intermediate layer substantially increasing in amount in each intermediate layer in proportion to distance from said substrate, said substrate having crystal lattice dimensions smaller than those of said intermediate layers, and forming at least one semiconductor layer on said intermediate layers, said semiconductor layer being chemically formed by elements of said substrate with at least one additional complementary element, said substrate having crystal lattice dimensions smaller than those of said semiconductor layer, wherein the relative increase of said crystal lattice dimensions of a first intermediate layer in closest proximity to said substrate is chosen to be less than 1.2×10 -3 relative to the crystal lattice dimensions of said substrate, and wherein the relative increase of the crystal lattice dimensions a n of the n th intermediate layer to the crystal lattice dimensions a n-1 of the n-1 intermediate layer is chosen to be equal to αn where α is a coefficient between 6×10 -4 and 1.6×10 -3 .