The onset of surface blistering in hydrogen-implanted single crystalline silicon was studied. A combination of atomic force microscopy and optical measurements shows that hydrogen-containing platelets grow laterally below silicon surface until they suddenly pop up as surface blisters due to the internal hydrogen pressure after a critical size has been reached. Experimentally and theoretically, the critical size of the onset blisters was found to increase with increasing implantation depth or top layer thickness. (C) 1999 American Institute of Physics. [S0003-6951(99)01207-3].