SELECTIVE ETCHING OF ALXGA1-XAS AND IN(ALXGA1-X)AS ALLOYS IN SUCCINICACID HYDROGEN-PEROXIDE SOLUTIONS

Succinic acid-hydrogen peroxide solutions were used to etch AlxGa1-xAs and In(AlxGa1-x)As alloys, and the etch rates were investigated with the varying alloy mole fractions. It was found that AlxGa1-xAs (x less -than-or-equal-to 0.4) may be selectively etched over AlxGa1-yAs (y gr eater-than-or-equal-to 0.5), with a selectivity better than 150. Exten ded surface exposure to air was found to affect the etch rates, most i nterestingly for Al0.4Ga0.6As. In the In(AlxGa1-x)As system, alloys wi th x less-than-or-equal-to 0.8 can be preferentially etched over In0.5 2Al0.48As with a selectivity of better than 20.