LETTER TO THE EDITOR: Substrate temperature dependence of GaAs etch rates in CH4:H2 MORIE
The dependence of GaAs etch rates on cathode temperature has been investigated in the range of 285-365 K for a CH4:H2 RF plasma. Results indicate that the apparent activation energy Ea, is strongly influenced by the CH4 partial pressure. GaAs etch rates have an activated temperature dependency with measured values of Ea, varying from approximately=0.7 eV in H2 down to approximately=6.5 meV under high CH4 partial pressures. Thus GaAs etch rates become progressively independent of temperature with increasing CH4 partial pressure. Consequently etch rate stability is enhanced at high CH4 partial pressures, thereby enabling reproducible deep mesa etching.