Transistor and method for fabricating the same
A transistor and a method for fabricating the transistor are provided. The semiconductor structure transistor includes a base, a low-dimensional material layer, a plurality of spacers, a source, a drain, and a gate stack. The low-dimensional material layer is provided above the base. The plurality of spacers is provided on a surface of the low-dimensional material layer away from the base and spaced apart from each other. The source and the drain are provided on the surface of the low-dimensional material layer away from the base, respectively. The gate stack is provided on the surface of the low-dimensional material layer away from the base and between the source and the drain, in which the gate stack, the source and the drain are separated by the spacers, and in contact with the spacers, respectively. Therefore, the transistor has advantages of excellent comprehensive performance, high process compatibility, and good device uniformity.
1 . A method for fabricating a transistor, comprising:
forming a low-dimensional material layer above a base,
forming spacers on a surface of the low-dimensional material layer away from the base, the spacers being spaced apart from each other;
forming a source and a drain on the surface of the low-dimensional material layer away from the base;
forming a gate stack on the surface of the low-dimensional material layer away from the base and between the source and the drain,
wherein the gate stack, the source and the drain are separated by the spacers, and in contact with the spacers, respectively;
wherein forming the spacers comprises:
depositing a protective material layer and an insulating material layer in sequence on the surface of the low-dimensional material layer away from the base;
patterning the insulating material layer and the protective material layer in sequence to form a plurality of spaced first grooves to expose a first part of the low-dimensional material layer;
growing a spacer material layer in the plurality of first grooves and on a surface of the insulating material layer away from the base; and
patterning the spacer material layer to form the spacers, wherein:
growing the spacer material layer is performed by at least one selected from atomic layer deposition, chemical vapor deposition and physical vapor deposition; and/or
patterning the spacer material layer is performed by at least one selected from reactive ion etching and chemical mechanical polishing.
2 . The method according to claim 1 , wherein the insulating material layer comprises a plurality of stacked insulating sub-layers with a thickness of 100 to 3000 nm, wherein a deposition temperature of the insulating material layer is lower than 400° C., and/or a deposition temperature of the protective material layer is lower than 400° C.
3 . The method according to claim 1 , wherein patterning the protective material layer comprises chemically etching the protective material layer with a reactive solution or a reactive gas, and washing the etched protective material layer with water, wherein:
the reactive solution comprises an acidic solution or an alkaline solution;
the acidic solution comprises at least one selected from hydrochloric acid, acetic acid, nitric acid, phosphoric acid and sulphuric acid;
the alkaline solution comprises at least one selected from potassium hydroxide, sodium hydroxide and tetramethylammonium hydroxide;
the reactive gas comprises at least one selected from hydrogen chloride and hydrogen fluoride;
a material for the protective material layer comprises at least one selected from yttrium oxide, lanthanum oxide, scandium oxide, silicon oxide, and aluminum oxide; and/or
a thickness of the protective material layer is 3 to 50 nm.
4 . The method according to claim 1 , further comprising:
before depositing the protective material layer on the surface of the low-dimensional material layer away from the base, forming another protective material layer between the base and the low-dimensional material layer.
5 . The method according to claim 1 , wherein forming the source and the drain comprises:
patterning the insulating material layer and the protective material layer between two adjacent spacers in sequence to form a plurality of second grooves to expose a second part of the low-dimensional material layer;
forming in the plurality of second grooves the source and the drain separated by the spacers.
6 . The method according to claim 5 , wherein forming the source and the drain in the plurality of second grooves comprises:
forming a metal material layer in the plurality of second grooves and on surfaces of the spacers and the insulating material layer away from the base;
forming a dielectric protection material layer on a surface of the metal material layer away from the base;
patterning the dielectric protection material layer to expose the metal material layer on the surfaces of the spacers and the insulating material layer away from the base; and
removing the metal material layer on the surfaces of the spacers and the insulating material layer away from the base to obtain the source and the drain, wherein:
forming the metal material layer is performed by physical vapor deposition or atomic layer deposition;
forming the dielectric protection material layer is performed by at least one of atomic layer deposition, chemical vapor deposition, and physical vapor deposition; and/or
patterning the dielectric protection material layer is performed by at least one selected from reactive ion etching and chemical mechanical polishing.
7 . The method according to claim 5 , wherein forming the gate stack comprises:
patterning the insulating material layer and the protective material layer between two spacers between the source and the drain in sequence to form a third groove to expose a third part of the low-dimensional material layer; and
forming the gate stack in the third groove, wherein:
a gate dielectric layer and a gate metal layer are sequentially formed in the third groove to form the gate stack; and
the gate dielectric layer and the gate metal layer are formed by at least one of atomic layer deposition, chemical vapor deposition and physical vapor deposition.
8 . The method according to claim 7 , further comprising:
cleaning the exposed first part, the exposed second part and the exposed third part of the low dimensional material layer by wet cleaning after forming the plurality of first grooves, the second grooves and the third grooves, respectively.
9 . The method according to claim 1 , wherein the low-dimensional material layer comprises a plurality of low-dimensional material sub-layers, wherein the protective material layer is located between two adjacent low-dimensional material sub-layers.