1. A method of manufacturing a semiconductor piece, comprising the steps of: (i) stacking a sacrificial layer and a semiconductor layer on a substrate in this order, and repeating the stacking so as to form the semiconductor layers on the substrate, the number of the semiconductor layers being at least two; (ii) etching part of the sacrificial layers and part of the semiconductor layers so as to divide the semiconductor layers into pieces; and (iii) removing the sacrificial layers so as to separate the pieces from the substrate.