Evolution of surface morphology of Si-trench sidewalls during hydrogen annealing

We have investigated the effect of high temperature hydrogen annealing on the sidewall morphology of micron-sized trenches formed on a Si(0 0 1) substrate by atomic force microscopy.We show that high temperature hydrogen annealing is effective for the flattening of as-etched rough surfaces and yields surfaces having atomic steps and terraces when the annealing temperature exceeds 1000 8C. We also found that, during hydrogen annealing, large-scale structural changes accompanied trench corner rounding and occurred through the movement of steps on the sidewall surfaces.