In some embodiments, a semiconductor structure includes first and second GAA structures configured to form corresponding similar first and second circuits. At least one of the first or second GAA structure includes at least one GAA device. A GAA device of the at least one GAA device includes at least one nanowire and a gate region. A nanowire of the at least one nanowire has a cross-section asymmetrical with respect to a middle line of the cross-section. The cross-section has first and second end lines substantially parallel the middle line. The first end line is shorter than the second end line. The gate region wraps all around part of the nanowire. The first and second GAA structures have substantially a same of a number of GAA devices in the at least one GAA device configured to have current flow from the first end line to the second end line.