Methods of forming an array of memory cells, methods of forming a plurality of field effect transistors, methods of forming source/drain regions and isolation trenches, and methods of forming a series of spaced trenches into a substrate

Abstract

A method of forming a series of spaced trenches into a substrate includes forming a plurality of spaced lines over a substrate. Anisotropically etched sidewall spacers are formed on opposing sides of the spaced lines. Individual of the lines have greater maximum width than minimum width of space between immediately adjacent of the spacers between immediately adjacent of the lines. The spaced lines are removed to form a series of alternating first and second mask openings between the spacers. The first mask openings are located where the spaced lines were located and are wider than the second mask openings. Alternating first and second trenches are simultaneously etched into the substrate through the alternating first and second mask openings, respectively, to form the first trenches to be wider and deeper within the substrate than are the second trenches. Other implementations and embodiments are disclosed.