DESIGN AND ANALYSIS OF INAS ALSB BALLISTIC CONSTRICTIONS FOR HIGH-TEMPERATURE OPERATION AND LOW GATE LEAKAGE/

Split-gate ballistic constrictions have been fabricated on two separat e InAs/AlSb quantum well heterostructures. Constrictions in the initia l material layer structure displayed quantized conductance to temperat ures as high as 30 K, but suffered from poor reliability and large gat e leakage current. Self-consistent Schrodinger-Poisson calculations in dicate that donorlike states at the InAs-AlSb interface may aggravate the problem of gate leakage. Constrictions fabricated on an improved l ayer structure had gate leakage currents several orders of magnitude l ower than in the original layer structure. This allowed measurement of quantized conductance with a dc measurement, up to bias voltages of 8 mV.