Strain fields near InGaP surfaces due to bias sputtering are affected by the bias voltage used in this surface-cleaning treatment. Measured rocking curves of an InGaP113 reflection under grazing X-ray incidence conditions consisted of a main peak and broad sub peaks. The shape of the broad sub peaks was due to a compositional fluctuation near the subsurface. Changes in the main peak versus bias voltage curves indicate that bias sputtering introduces a tensile strain to the InGaP surface. Furthermore, changes in the sub peak versus supplied bias voltage curves indicate that excessive sputtering generates a heavy compositional fluctuation near the InGaP subsurface. In conclusion, based on the measured strain and compositional fluctuation, a heavy compositional fluctuation generally causes a large tensile strain near the InGaP surface. (C) 2003 Elsevier Science B.V. All rights reserved.