CMOS transistor having different PMOS and NMOS gate electrode structures and method of fabrication thereof
First Claim
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1. A method of fabricating a semiconductor device, comprising:
- forming a gate oxide layer on a semiconductor substrate, a device isolation region being formed on the substrate to define an NMOS region and a PMOS region;
sequentially forming a silicon germanium layer and an amorphous conductive layer on the gate oxide layer;
removing the amorphous conductive layer and the silicon germanium layer in the NMOS region;
forming a polysilicon layer on the semiconductor substrate in the NMOS region; and
until the gate insulating layer is exposed, patterning the stacked conductive layers to form gate electrodes the NMOS and PMOS regions respectively.
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Abstract
In a CMOS semiconductor device using a silicon germanium gate and a method of fabricating the same, a gate insulating layer, a conductive electrode layer that is a seed layer, a silicon germanium electrode layer, and an amorphous conductive electrode layer are sequentially formed on a semiconductor substrate. A photolithographic process is then carried out to remove the silicon germanium electrode layer in the NMOS region, so that the silicon germanium layer is formed only in the PMOS region and is not formed in the NMOS region.
39 Citations
25 Claims
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1. A method of fabricating a semiconductor device, comprising:
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forming a gate oxide layer on a semiconductor substrate, a device isolation region being formed on the substrate to define an NMOS region and a PMOS region;
sequentially forming a silicon germanium layer and an amorphous conductive layer on the gate oxide layer;
removing the amorphous conductive layer and the silicon germanium layer in the NMOS region;
forming a polysilicon layer on the semiconductor substrate in the NMOS region; and
until the gate insulating layer is exposed, patterning the stacked conductive layers to form gate electrodes the NMOS and PMOS regions respectively. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of fabricating a semiconductor device, comprising:
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forming a gate oxide layer on a semiconductor substrate, a device isolation region being formed on the substrate to define an NMOS region and a PMOS region;
forming a lower polysilicon electrode seeding layer on the gate oxide layer;
forming a silicon germanium electrode layer on the lower polysilicon electrode seeding layer;
forming an amorphous electrode layer on the silicon germanium electrode layer;
forming a mask pattern on the amorphous electrode layer in the PMOS region so as to expose the NMOS region;
dry-etching the amorphous electrode layer and a portion of the underlying silicon germanium electrode layer in the NMOS region exposed by the mask pattern;
removing the mask pattern;
selectively wet-etching a residue of the silicon germanium electrode layer exposed by the dry etch down to a top surface of the lower polysilicon electrode seeding layer in the NMOS region;
forming upper polysilicon electrode layers on the lower polysilicon electrode seeding layer in the NMOS region and the silicon germanium electrode layer in the PMOS region, respectively; and
patterning the stacked electrode layers to form gate electrodes in the NMOS and PMOS regions, respectively. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21)
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22. A semiconductor device having an NMOS transistor and a PMOS transistor defined in respective NMOS and PMOS regions respectively of a semiconductor substrate, each transistor having a gate insulating layer between a gate electrode and the semiconductor substrate;
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wherein the gate electrode of the NMOS transistor consists of a lower polysilicon layer and an upper polysilicon layer which are sequentially stacked on the gate insulating layer;
wherein the gate electrode of the PMOS transistor consists of a lower polysilicon layer, a silicon germanium layer, a diffusion barrier amorphous silicon layer, and an upper polysilicon layer which are sequentially stacked on the gate insulating layer; and
wherein each of the transistors includes a source/drain regions formed in the semiconductor substrate adjacent side portions of the respective gate electrodes. - View Dependent Claims (23, 24, 25)
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