This paper presents our studies of the growth of InAs/GaAs and GaSb/GaAs heterojunctions by molecular beam epitaxy and their applications in fabricating the InAs-AlSb-GaSb interband tunneling devices. The Hall effect and x-ray diffraction were used to determine the optimum growth conditions for the layers. In addition, the qualities of the InAs and GaSb epilayers, grown under their optimum conditions, were compared. The full width at half maximum (FWHM) from the x-ray diffraction for a GaSb epilayer is about 50 arcsec narrower than an InAs epilayer of the same thickness. The narrower FWHM and excellent surface morphology of the GaSb layer have led us to grow the polytype heterostructure on a p+-GaAs substrate using a p+-GaSb as the buffer layer. The polytype tunneling structures grown on GaAs substrates under these conditions show good negative differential resistance properties. Five different interband tunneling structures are compared and discussed in terms of their peak-current densities and peak-to-valley current ratios.
- InAs-AlSb-GaSb tunnel diodes
- negative resistance
- semiconductor devices and materials