Method of fabricating transistor including buried insulating layer and transistor fabricated using the same
In a method of fabricating a transistor including a buried insulating layer and transistor fabricated using the same, the method includes sequentially forming a sacrificial layer and a top semiconductor layer on a single crystalline semiconductor substrate. A gate pattern is formed on the top semiconductor layer. A sacrificial spacer is formed to cover sidewalls of the gate pattern. An elevated semiconductor layer is grown on a portion of the top semiconductor layer adjacent to the sacrificial spacer. The sacrificial spacer is removed. A portion of the top semiconductor layer from which the sacrificial spacer is removed is etched until the sacrificial layer is exposed, thereby forming a recess, which separates the top semiconductor layer into a first top semiconductor layer pattern and a second top semiconductor layer pattern, which remain under the gate pattern and the elevated semiconductor layer, respectively. The sacrificial layer is selectively removed. A buried insulating layer is formed to fill a region from which the sacrificial layer is removed. A buried semiconductor layer is grown in the recess. An extending recess extends from the recess and is formed to expose the semiconductor substrate. The extending recess separates the buried insulating layer into a first buried insulating layer pattern and a second buried insulating layer pattern, which are self-aligned to the first and second top semiconductor layer patterns, respectively.
1. A MOS transistor comprising:
a single crystalline semiconductor substrate;
a first top semiconductor layer pattern disposed on the semiconductor substrate;
second top semiconductor layer patterns disposed on the semiconductor substrate at opposite sides of and spaced apart from the first top semiconductor layer pattern;
a first buried insulating layer pattern interposed between the first top semiconductor layer pattern and the semiconductor substrate;
second buried insulating layer patterns interposed between the second top semiconductor layer patterns and the semiconductor substrate;
buried semiconductor layers interposed between the first top semiconductor layer pattern and the second top semiconductor layer patterns and between the first buried insulating layer pattern and the second buried insulating layer patterns, the buried semiconductor layers being in contact with the semiconductor substrate;
a gate pattern disposed on the first top semiconductor layer pattern and including a gate electrode; and
source/drain regions formed in the buried semiconductor layers and the second top semiconductor layer patterns.
2. The transistor according to claim 1 , wherein the single crystalline semiconductor substrate is a single crystalline silicon substrate.
3. The transistor according to claim 1 , wherein the first top semiconductor layer pattern and the second top semiconductor layer patterns are single crystalline silicon layer patterns.
4. The transistor according to claim 3 , wherein each of the single crystalline silicon layer patterns has a thickness of about 5 to 50 nm.
5. The transistor according to claim 1 , wherein the first buried insulating layer pattern and the second buried insulating layer patterns are formed of a silicon oxide layer or a silicon nitride layer.
6. The transistor according to claim 5 , wherein the first buried insulating layer pattern and the second buried insulating layer patterns are formed of a thermal oxide layer.
7. The transistor according to claim 1 , wherein each of the first buried insulating layer pattern and the second buried insulating layer patterns has a thickness of about 10 to 100 nm.
8. The transistor according to claim 1 , wherein the buried semiconductor layer is a single crystalline semiconductor layer, which is grown using a selective epitaxial growth process.
9. The transistor according to claim 8 , wherein the buried semiconductor layer is one selected from a group consisting of a silicon layer, a silicon germanium layer, and a silicon carbide layer.
10. The transistor according to claim 1 , wherein the gate pattern further comprises:
a gate insulating layer interposed between the gate electrode and the first top semiconductor layer pattern; and
a capping layer pattern deposited on the gate electrode.
11. The transistor according to claim 1 , further comprising:
a gate spacer disposed on the buried semiconductor layers and covering sidewalls of the gate pattern; and
a sidewall oxide layer interposed between the gate spacer and the gate electrode.
12. The transistor according to claim 1 , further comprising elevated semiconductor layers, which are grown on the second top semiconductor layer patterns.
13. The transistor according to claim 12 , wherein the elevated semiconductor layers are single crystalline silicon layers, which are grown using a selective epitaxial growth process.
14. The transistor according to claim 12 , further comprising metal silicide layers disposed on the elevated semiconductor layers.
15. A MOS transistor comprising:
a single crystalline semiconductor substrate;
a first top semiconductor layer pattern disposed on the semiconductor substrate;
second top semiconductor layer patterns disposed on the semiconductor substrate at opposite sides of and spaced apart from the first top semiconductor layer pattern;
buried semiconductor layers interposed between the first top semiconductor layer pattern and the second top semiconductor layer patterns;
a buried insulating layer interposed between the semiconductor substrate and the first top semiconductor layer pattern, between the semiconductor substrate and the buried semiconductor layers, and between the semiconductor substrate and the second top semiconductor layer patterns;
a gate pattern disposed on the first top semiconductor layer pattern and including a gate electrode;
a gate spacer disposed on the buried semiconductor layers and covering sidewalls of the gate pattern;
a sidewall oxide layer interposed between the gate spacer and the gate electrode;
elevated semiconductor layers disposed on at least the second top semiconductor layer patterns; and
source/drain regions formed in the buried semiconductor layers, the elevated semiconductor layers, and the second top semiconductor layer patterns.