Forming crossbar and non-crossbar transistors on the same substrate
A method of forming a transistor structure is provided. The method includes forming on a substrate first and second mandrels for forming two-dimensional (2D) transistor fin elements defining a pitch gap region, depositing and anisotropically etching back the first spacer material to form first and second spacers in and around the first and second mandrels, respectively, conformally depositing and anisotropically etching back second spacer material around the first and second spacers and in the pitch gap region to define space for forming an odd number of one-dimensional (1D) transistor fin elements in the pitch gap region and depositing and anisotropically etching back the first spacer material in the space with enough cycles to fill the space to form a third spacer.
1 . A precursor structure formed during formation of a transistor structure, the precursor structure comprising:
a first hard mask disposed on a substrate;
a second hard mask disposed on the first hard mask to form first and second mandrels defining a pitch gap region between the first and second mandrels;
first spacer material deposited on the first hard mask in and around the first and second mandrels to assume shapes of two-dimensional (2D) transistor fin elements; and
second spacer material conformally deposited in the pitch gap region to define space having a shape of a one-dimensional (1D) transistor fin element,
the first and second hard masks are formed of different hard mask materials and the second spacer material differs from the first spacer material.
2 . The precursor structure according to claim 1 , wherein the second spacer material is a same material as that of the second hard mask.
3 . The precursor structure according to claim 1 , wherein a critical dimension (CD) of the space differs from a corresponding CD of the 2D transistor fin elements.
4 . The precursor structure according to claim 1 , wherein the shapes of the 2D transistor fin elements are H-shapes.
5 . The precursor structure according to claim 1 , wherein the shape of the 1D transistor fin element is straight.