The electron concentration at anN‐AlGaAs/GaAs interface is shown to be spatially modulated at low temperatures by the selective photoionization of deep donors in AlGaAs using two interfering laser beams. The charge pattern thus formed is persistent and detected by measuring the anisotropy of the channel conductivity. Grating patterns with a period as small as 0.6 &mgr;m were successfully recorded in accordance with the prediction that spatial resolution comparable with the AlGaAs layer thickness (∼0.1 &mgr;m) will be achieved.