LATERAL RESOLUTION IN LASER-PATTERNED THERMAL-PROCESSING OF GAAS

Time-dependent two-dimensional calculations are employed to estimate t he limits placed, by thermal diffusion, on the lateral resolution of t hermally-activated excimer-laser-induced patterned processing of GaAs. Sinusoidal and rectangular fluence profiles are used for holographic or projection exposure. Despite thermal diffusion, holographic exposur e can result in feature sizes well into the nanostructure regime, exce pt for low activation energy processes conducted at low peak temperatu res. In projection patterning, pattern fidelity is severely affected b y thermal diffusion. In this case, reasonably rectangular process prof iles can only be obtained for feature sizes as large as several micron s, unless hard process thresholds and/or stopping layers are involved. (C) 1998 Elsevier Science B.V.