Rapid thermal annealing effects on step-graded InAlAs buffer layer and In[sub 0.52]Al[sub 0.48]As/In[sub 0.53]Ga[sub 0.47]As metamorphic high electron mobility transistor structures on GaAs substrates.

A step-graded InAlAs buffer layer and an In[sub 0.52]Al[sub 0.48]As/In[sub 0.53]Ga[sub 0.47]As metamorphic high electron mobility transistor (MM-HEMT) structures were grown by molecular beam epitaxy on GaAs (001) substrates, and rapid thermal annealing was performed on them in the temperature range 500–800 °C for 30 s. The as-grown and annealed samples were investigated with Hall measurements, and 77 K photoluminescence. After rapid thermal annealing, the resistivities of step-graded InAlAs buffer layer structures became high. This can avoid leaky characteristics and parasitic capacitance for MM-HEMT devices. The highest sheet carrier density n[sub s] and mobility μ for MM-HEMT structures were achieved by annealing at 600 and 650°C, respectively. The relative intensities of the transitions between the second electron subband to the first heavy-hole subband and the first electron subband to the first heavy-hole subband in the MM-HEMT InGaAs well layer were compared under different annealing temperatures. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]