p-Channel MODFET´s using GaAlAs/GaAs two-dimensional hole gas

p-channel MODFET´s were fabricated in the GaAlAs/GaAs system and the properties of the hole gas system tested to ascertain its suitability for complementary logic. The Hall mobilities on a Ga.5Al.5As/GaAs modulation-doped hole gas structure were measured to be 3650 cm²V^-1s^-1and 54000 cm²V^-1s^-1with sheet carrier concentration of 1 × 10¹²cm^-2and 7.76 × 10¹¹cm^-2at 77 and 4.2 K, respectively. The measured transconductances of 1.5-µm gate-length MODFET´s on this structure were measured to lie in the range of 28-35 mS.mm^-1at 77 K. The field mobility measured on long gate-length MODFET´s was approximately 3200 cm²V^-1s^-1at 77 K. Using test structures for measuring current voltage characteristic in the hole-gas system, low field drift mobility was measured to be 3000 cm²V^-1s^-1and velocities of 3 5 × 10⁶cm.s^-1were measured at electric fields of 3-4 kV.cm^-1at 77 K. The Schottky barriers showed low leakage and a barrier height of 0.7 to 0.8 eV. Calculations indicate that transconductances of approximately 100 mS.mm^-1should be achievable in this system for similar gate lengths.