HIGH-PERFORMANCE HIGHLY STRAINED GA0.23IN0.77AS/AL0.48IN0.52AS MODFETS OBTAINED BY SELECTIVE AND SHALLOW ETCH GATE RECESS TECHNIQUES

Record high f(T) . L(g) products of 57 and 46 GHz . mu-m have been achieved in Ga1-xInxAs / AlInAs MODFET's with a strain compensated channel of x = 0.77 and a lattice-matched channel of x = 0.53, respectively. Although g(m) as high as 950 mS / mm has been obtained by conventional deep recess for the gate, these latter devices show prominent kink effect which lowers f(T) and the voltage gain. By limiting the depth of final nonselective recess etch to 3 nm with the help of selective stop etches, f(T) as high as 47 GHz and g(m) as high as 843 mS / mm have been achieved for MODFET's with x = 0.77 and L(g) = 1.1-mu-m.