The present invention provides a container for holding product therein during shipment and being returned for reuse that has a body, tracks attached to opposite sides of the body, and a plurality of support member assemblies extending between the tracks for supporting dunnage. In this method, no contact hole is formed in the region having the defect therein, the cell is considered as a defective one, yet a word line and a bit line are not short-circuited through the contact hole, and makes it possible to avoid the short-circuiting by only applying a redundancy to the bit line as conventionally employed. Dopants are selectively implanted through a horizontal surface of the mesa step into a portion of the drift layer beneath the mesa step to form a buried junction extension in the drift layer.