A SICL4 REACTIVE ION ETCHING AND LASER REFLECTOMETRY PROCESS FOR ALGAAS GAAS HBT FABRICATION/

The potentialities of SiCl4 reactive ion etching associated with laser reflectometry as an etch monitoring system are investigated. This tec hnique allows accurate and reliable mesa etchings for the fabrication of GaAlAs/GaAs HBT. Two different processes with a 700 Angstrom/min et ch rate for the emitter mesa and a 1000 Angstrom/min etch rate for bas e and insulation mesas using a reflectometry calibration sample were o ptimized. A precision in the order of 4% on the resulting etched depth was achieved in both cases. Copyright (C) 1996 Elsevier Science Ltd