Dual workfunction silicide diode
AssigneeInternational Business Machines Corporation
InventorsHaining S. Yang, Xiangdong Chen
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Abstract
A CMOS diode and method of making it are disclosed. In one embodiment, the diode comprises a silicon substrate having an N doped region and a P doped region. A first silicide region is formed on the N doped region of the silicon substrate, and a second silicide region formed on the P doped region of the silicon substrate. The first silicide region is comprised of a material having a bandgap value lower than the bandgap value of the material comprising the second silicide region. The result is a diode where the workfunction of each region of silicide more closely matches the workfunction of the doped silicon it contacts, resulting in reduced contact resistance. This provides for a diode with improved performance characteristics.
Claims1
A method of fabricating a CMOS diode comprising the steps of:
- forming a gate structure on a silicon substrate;
- doping the silicon substrate to form a P doped region and an N doped region on the silicon substrate, wherein the step of doping the silicon substrate to form the P doped region and the N doped region on the silicon substrate is performed via ion implantation;
- forming an N-side hardmask, wherein the N-side hardmask is comprised of silicon oxide with a thickness in the range of about 20 nanometers to about 80 nanometers;
- forming a P-type silicide region on the P doped region of the silicon substrate;
- removing the N-side hardmask;
- forming a P-side hardmask, wherein the P-side hardmask is comprised of silicon oxide with a thickness in the range of about 20 nanometers to about 80 nanometers;
- forming an N-type silicide region on the N doped region of the silicon substrate;
- removing the P-side hardmask;
- and
- forming a nitride layer over the silicon substrate, gate structure, and silicide, the step of forming a nitride layer comprises depositing a nitride layer using a chemical vapor deposition process;
- and
- wherein the step of forming an N-type silicide region comprises the steps of:
- sputtering a metal selected from the group consisting essentially of Erbium, Ytterbium, Yttrium, Holmium, Terbium, Gadolinium, Lutetium, Dysprosium, and Scandium;
- and
- annealing the metal at a temperature in the range of about 200 degrees Celsius to about 550 degrees Celsius.
Dependencies are inferred from the claim text.