CHARACTERISTICS OF A IN-0.52(ALXGA1-X)(0.48)AS 0-LESS-THAN-OR-EQUAL-TO-X-LESS-THAN-OR-EQUAL-TO-1) HETEROJUNCTION AND ITS APPLICATION ON HEMTS/

The quarternary In-0.52(AlxGa1-x)(0.48)As compound on InP substrates i s an important material for use in optoelectronic and microwave device s. We have systematically investigated the electrical properties of qu arternary In-0.52(AlxGa1-x)(0.48)As layers, and found that a 10% addit ion of Ga atoms into the InAlAs layer improves the Schottky diode perf ormance. The energy bandgap (E-g) for the In-0.52(AlxGa1-x)(0.48)As la yer was (0.806 + 0.711x) eV, and the associated conduction-band discon tinuity (Delta E-c), in the InAlGaAs/In0.53Ga0.47As heterojunction, wa s around (0.68 +/- 0.01)Delta E-g. Using this high quality In-0.52(Al0 .9Ga0.1)(0.48)As layer in the Schottky and buffer layers, we obtained quarternary In-0.52(Al0.9Ga0.1)(0.48)As/In0.53Ga0.47As HEMT's. This qu arternary HEMT revealed excellent dc and microwave characteristics. In comparison with the conventional InAlAs/InGaAs HEMT's, quarternary HE MT's demonstrated improved sidegating and device reliability.