|
InP is a very promising material for electronic and optoelectronic devices, especially for heterojunction devices employing InGaAs as the low energy gap material. However, the low metal-semiconductor barrier height of n-InP (phib less than or equal to 0.5 eV) and the lack of reliable oxide-insulator technology, limit the number of applications severely. Here, the need for an oxide-insulator layer is eliminated with a simple one step deposition technique. We report the enhancement of the Schottky barrier height in n-InP using a dry, room temperature indium tin oxide (ITO) film deposition technique in a controlled oxygen and argon partial pressure environment. This process appears to produce a stable reproducible surface. Resistivity values as low as 2 by 10-5 (Omega) cm and optical transmission values greater than 90% in the visible and near-IR region of the spectrum were obtained. Barrier height values as high as phib equals 0.89 eV have been obtained from current-voltage (I-V) characteristics that were linear over several orders of magnitude of current with an interface trap time constant of 7.07 by 10-6s obtained from conductance-frequency (G-f) measurements. The enhancement in the barrier height is explained by an analysis of the ITO/InP interface. This process is being investigated for fabricating a highly transparent ITO gate electrode to an InP optical field effect transistor (OPFET) structure.
|
