This letter reports on the spike anneal temperature influence on the retention time of 1T-dynamic random access memory cells using a single silicon-on-insulator transistor on ultrathin buried oxide wafers. A 20 $^{\circ}{\rm C}$ temperature difference (from 1070 $^{\circ}{\rm C}$ to 1050 $^{\circ}{\rm C}$ ) in the peak process temperature during the spike anneal after the source/drain implantation caused an order of magnitude increment in the retention time. The lower temperature analyzed (1050 $^{\circ}{\rm C}$ ) increases the retention time up to 100 ms because of the lower drain electrical field and tunneling current.