quite possible there's nothing wrong with the sensor.

you need to see a tech to determine what the sensor IS reading and move on from there.

And you could replaçe it 100 more times and it still won't cure it. Thats because the fault code isn't telling you what the fault is, it's telling where the fault was reported from. You now need to do some diagnostic work to find out why the engine is running inefficiently which is causing the O2 sensor to read what it is. There could be any number of reasons which might or might not be obvious. I'd start by doing some live data checks, and check the fuel trim readings.