New Pseudomorphic MODFETs Utilizing Ga sub (0.47-u) In sub (0.53+u) As/Al sub (0.48+u) In sub (0.52-u) As Heterostructures.

A new pseudomorphic modulation-doped field-effect transistor (MODFET) utilizing a Ga sub (0.47-u) In sub (0.53+u) As/Al sub (0.48+u) In sub (0.52-u) As (u=0.07) heterojunction on InP substrate is proposed, fabricated and characterized. The molecular beam epitaxially (MBE) grown heterostructure samples have sheet carrier densities in excess of 10 sup 12 cm sup (-2) and exhibit electron mobilities as high as 12050, 59970, and 87300 cm sup 2 /V-sec at 300, 77, and 4.2K. The samples do not exhibit light sensitivity of persistent photoconductivity effects in any significant way. MODFETs fabricated from these samples exhibit DC transconductances as high as 271 mS/mm and 227 mS/mm at room temperature for 1.6microns and 2.9microns gate-lengths respectively.