diff --git a/libs/wlgen/wlgen/rta.py b/libs/wlgen/wlgen/rta.py
index 3daf411e98b7526dd0983876c7a1b74d35b6b366..4d3f2c766bf87b9320ac617ca109a210d04114a5 100644
--- a/libs/wlgen/wlgen/rta.py
+++ b/libs/wlgen/wlgen/rta.py
@@ -319,7 +319,7 @@ class RTA(Workload):
                 if task['delay'] > 0:
                     task['delay'] = int(task['delay'] * 1e6)
                     task_conf['phases']['p000000'] = {}
-                    task_conf['phases']['p000000']['sleep'] = task['delay']
+                    task_conf['phases']['p000000']['delay'] = task['delay']
                     self.logger.info(' | start delay: %.6f [s]',
                             task['delay'] / 1e6)