Method for forming a non-epitaxial bipolar integrated circuit
First Claim
1. A method for forming an integrated circuit comprising;
- forming in a silicon substrate of one-type conductivity, recessed silicon dioxide regions extending into said substrate and laterally enclosing at least one silicon substrate region of said one-type conductivity,directing a beam of ions of opposite-type conductivity impurities at said enclosed silicon region at energy and dosage levels sufficient to form a first region of said opposite-type conductivity defined and fully enclosed laterally by said recessed silicon dioxide regions,said opposite-type conductivity impurity having a concentration peak at a point below the surface of said first regionforming a second region of said one-type conductivity extending from said surface into said opposite-type conductivity region to a point between said concentration peak and said surface, andforming a second region of said opposite-type conductivity extending from said surface part way into said second region of one-type conductivity.
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Abstract
A method for forming a non-epitaxial bipolar integrated circuit comprising first forming in a silicon substrate of one-type of conductivity, recessed silicon dioxide regions extending into the substrate and laterally enclosing at least one silicon substrate region of said one-type conductivity. Then, forming by ion implantation the first region of opposite-type conductivity which is fully enclosed laterally by said recessed silicon dioxide. This region is formed by directing a beam of ions of opposite-type conductivity impurity at said enclosed silicon region at such energy and dosage levels that the opposite conductivity-type impurity introduced into the substrate in said region will have a concentration peak at a point below the surface of this first region. Then, a region of said one-type conductivity is formed which extends from the surface into said first opposite-type conductivity region to a point between said concentration peak and said surface. Next, a second region of said opposite-type conductivity is formed which extends from the surface part way into said region of one-type conductivity.
Preferably, the ion beam energy level is at least one MeV, and said concentration peak is at least one micron below the surface. It is further preferable that the energy and dosage levels of the beam of ions are selected so that the opposite-type conductivity impurity has a more gradual distribution gradient between the peak and the surface than between the peak and the junction of the first region with the substrate.
113 Citations
13 Claims
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1. A method for forming an integrated circuit comprising;
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forming in a silicon substrate of one-type conductivity, recessed silicon dioxide regions extending into said substrate and laterally enclosing at least one silicon substrate region of said one-type conductivity, directing a beam of ions of opposite-type conductivity impurities at said enclosed silicon region at energy and dosage levels sufficient to form a first region of said opposite-type conductivity defined and fully enclosed laterally by said recessed silicon dioxide regions, said opposite-type conductivity impurity having a concentration peak at a point below the surface of said first region forming a second region of said one-type conductivity extending from said surface into said opposite-type conductivity region to a point between said concentration peak and said surface, and forming a second region of said opposite-type conductivity extending from said surface part way into said second region of one-type conductivity. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification