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
.5
Al
.5
As/GaAs modulation-doped hole gas structure were measured to be 3650 cm
²
V
^-1
s
^-1
and 54000 cm
²
V
^-1
s
^-1
with sheet carrier concentration of 1 × 10
¹²
cm
^-2
and 7.76 × 10
¹¹
cm
^-2
at 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
^-1
at 77 K. The field mobility measured on long gate-length MODFET's was approximately 3200 cm
²
V
^-1
s
^-1
at 77 K. Using test structures for measuring current voltage characteristic in the hole-gas system, low field drift mobility was measured to be 3000 cm
²
V
^-1
s
^-1
and velocities of 3 5 × 10
⁶
cm.s
^-1
were measured at electric fields of 3-4 kV.cm
^-1
at 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
^-1
should be achievable in this system for similar gate lengths.