Parameters of ohmic contacts and consideration of the influence of actual sample sizes on the field dependence of the drift velocity in In0.16Ga0.84As layers

The method of obtaining ohmic contact to In 0.16 Ga 0.84 As layers is given in this paper. Contact resistance was measured by the transmission line method with radial geometry of contacts. It is shown that the Ni/Au/Ge/Au/Ge/Ni/Au-based contact is ohmic and reaches a minimum specific contact resistance of 6∙10 -5 Ohm∙cm 2 after annealing at 450 °C for 5 min. in the atmosphere of forming gas. To measure the dependence of the drift velocity on a high electric field, a sample with a specific shape was chosen that prevents the penetration of high field domains into the measurement area. An expression is obtained that allows for accurate calculation of electric field strength and drift velocity, considering the actual geometric sizes of the sample as determined by scanning electron microscopy. It is shown that the obtained expression allows us to obtain the same field dependences of the drift velocity for In 0.16 Ga 0.84 As samples with different geometrical sizes.