GaAs∕InGaP Selective Etching in BCl[sub 3]∕SF[sub 6] High-Density Plasmas

Selective dry etching of InGaP over GaAs in inductively coupled plasmas

“…This can be done with wet chemical etching solutions based on HCl, 15 but creation of small lateral dimension devices requires dry etching for high resolution pattern transfer. While selective etching of GaAs over InGaP is obtained with BCl 3 /SF 6 discharges that create involatile InCl x and InF x reaction products, 16 By exploiting the relatively high volatility of In etch products in CH 4 /H 2 discharges, we were able to obtain a maximum selectivity for InGaP over GaAs of ~20 at low ion energies and fluxes. Three different inert gas additives to CH 4 / H 2 were examined, with Ar producing higher selectivities than He or Xe.…”