An investigation of the electrochemical etching of

Results from an investigation of the electrochemical etching of silicon in KOH:H/sub 2/O and CsOH:H/sub 2/O solutions are presented. Current versus voltage (I-V) scans were performed on both n- and p-type silicon as a function of etchant concentration (20-60% by weight KOH and 25-70% by weight CsOH) and temperature (25-80 degrees C). Voltage scans were swept from potentials cathodic of the open-circuit potential (OCP) to potentials anodic of the passivation potential. The purpose of the I-V scans was to investigate systematically how varying etchant concentration and temperature affected the passivation potential and final passivation current density of n- and p-type silicon. The results of the I-V scans are used to help investigate conditions for optimizing the performance of three-electrode electrochemical etch stop on n/sup +/-p junction samples. A model is presented to describe the effect of reverse diode leakage on etch-stop performance which uses the previously measured electrochemical etching parameters. Experimental measurements of the etch stop are used to confirm the model.<>