Growth of epitaxial semiconductor material with improved crystallographic properties
First Claim
1. A method of forming an epitaxial semiconductor layer on a semiconductor substrate, the method comprising.placing a silicon substrate having a front surface within an epitaxial reaction chamber;
- adjusting the temperature of the substrate to a first temperature suitable for epitaxial silicon growth;
flowing a first flow of source gas into the reaction chamber at a first flow rate to grow a first epitaxial silicon layer on the front surface of the substrate to cover crystallographic defects in the front surface;
adjusting the temperature of the substrate to a second temperature suitable for epitaxial silicon growth, where the second temperature is lower than the first temperature; and
flowing a second flow of source gas into the reaction chamber at a second flow rate when the substrate is at the second temperature to grow a second epitaxial silicon layer on the first layer, where the second flow rate is higher than the first flow rate;
where the first and second layers each have a thickness, and the second layer is thicker than the first layer.
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Abstract
A method of growing epitaxial semiconductor layers with reduced crystallographic defects. The method includes growing a first epitaxial semiconductor layer on a semiconductor substrate under conditions of relatively high temperature and low source gas flow to heal defects in or on the surface of the substrate. Subsequently, a second epitaxial semiconductor layer is grown on the first layer under conditions of relatively low temperature and high source gas flow. The first epi layer acts as a low-defect seed layer by preventing defects in the surface of the substrate from propagating into the second epi layer. Optionally, a hydrogen chloride etch may be employed during a portion of the first epi layer growth to increase the efficacy of the first layer.
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Citations
10 Claims
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1. A method of forming an epitaxial semiconductor layer on a semiconductor substrate, the method comprising.
placing a silicon substrate having a front surface within an epitaxial reaction chamber; -
adjusting the temperature of the substrate to a first temperature suitable for epitaxial silicon growth;
flowing a first flow of source gas into the reaction chamber at a first flow rate to grow a first epitaxial silicon layer on the front surface of the substrate to cover crystallographic defects in the front surface;
adjusting the temperature of the substrate to a second temperature suitable for epitaxial silicon growth, where the second temperature is lower than the first temperature; and
flowing a second flow of source gas into the reaction chamber at a second flow rate when the substrate is at the second temperature to grow a second epitaxial silicon layer on the first layer, where the second flow rate is higher than the first flow rate;
where the first and second layers each have a thickness, and the second layer is thicker than the first layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification