Epitaxially extended polycrystalline structures utilizing a predeposit of amorphous silicon with subsequent annealing
First Claim
1. A method of forming a polycrystalline layer on an insulator coating of a silicon integrated circuitdepositing from a silicon forming gaseous phase a discrete amorphous silicon layer in a thickness not exceeding 1000 angstroms on said insulator coating at a temperature in the range of about 550°
- to 600°
C.;
heating the resultant structure at a temperature of about 800°
C. to convert said amorphous silicon layer to an equiaxial polycrystalline seed layer, andepitaxially extending the crystal grains of said polycrystalline seed layer by heating thereof in a silicon forming ambient at a temperature in the range of about 650°
to about 700°
C. for a time sufficient to grow the thickness desired.
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Abstract
Disclosed is a process for reducing microcracks and microvoids in the formation of polycrystalline (polysilicon) structures from initial layers of amorphous silicon by annealing. In annealing of amorphous silicon to the polycrystalline form, the crystal grains are thickness limited; and thus by maintaining the thickness below 1000 angstroms, the spacing between contrasting material forming the crystal grains can be minimized on anneal. The resultant equiaxial grains are used as seed crystals for epi-like growth of silicon from them into the required or desired layer thickness.
58 Citations
43 Claims
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1. A method of forming a polycrystalline layer on an insulator coating of a silicon integrated circuit
depositing from a silicon forming gaseous phase a discrete amorphous silicon layer in a thickness not exceeding 1000 angstroms on said insulator coating at a temperature in the range of about 550° - to 600°
C.;heating the resultant structure at a temperature of about 800°
C. to convert said amorphous silicon layer to an equiaxial polycrystalline seed layer, andepitaxially extending the crystal grains of said polycrystalline seed layer by heating thereof in a silicon forming ambient at a temperature in the range of about 650°
to about 700°
C. for a time sufficient to grow the thickness desired. - View Dependent Claims (2, 3, 4, 22, 23, 24, 25)
- to 600°
-
5. A method for forming polycrystalline layers on an insulator coating of an integrated circuit device, comprising:
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forming a first polycrystalline silicon layer on said insulator coating, forming a second insulator coating on said polycrystalline silicon layer, depositing from a silicon forming gaseous phase a discrete amorphous silicon layer in a thickness not exceeding 1000 angstroms on said second insulator coating at a temperature in the range of about 550°
C. to about 600°
C.,heating the resultant structure at a temperature of about 800°
C. to convert said amorphous layer to a second polycrystalline layer having equiaxial grains, andepitaxially extending the crystal grains of said second polycrystalline layer, by heating thereof in a silicon forming ambient at a temperature in the range of about 650°
C. to about 700°
C. for a time sufficient to grow the thickness desired. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43)
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Specification