Effect of external strain on the conductivity of AlGaN/GaN high-electron-mobility transistors

The changes in the conductance of the channel of Al0.3Ga0.7N/GaN high-electron-mobility transistor structures during the application of both tensile and compressive strain were measured. For a fixed Al mole fraction, the changes in the conductance were roughly linear over the range up to 2.7x10(8) N cm(-2), with coefficients for planar devices of -6.0+/-2.5x10(-10) S N-1 m(-2) for tensile strain and +9.5+/-3.5x10(-10) S N-1 m(-2) for compressive strain. For mesa-isolated structures, the coefficients were smaller due to the reduced effect of the AlGaN strain, with values of 5.5+/-1.1x10(-13) S N-1 m(-2) for tensile strain and 4.8x10(-13) S N-1 m(-2) for compressive strain. The large changes in the conductance demonstrate that simple AlGaN/GaN heterostructures are promising for pressure and strain sensor applications. (C) 2003 American Institute of Physics.