The improvement of Schottky barrier diodes fabricated only by B ion implantation doping accomplished by refinement of the electrode structure

Abstract

In this study, we fabricated p-type diamond Schottky barrier diodes, and performed selective B doping for the p-type channel and Ohmic region by double ion implantation. Schottky barrier diodes were redesigned the configuration and the shape of Ohmic and Schottky electrodes to improve device characteristics. The fabricated device exhibited a rectification ratio of approximately 2400 because of decreasing the parasitic resistance to 2.7 × 107 Ω and the ideality factor to 2.7. The Schottky barrier height was obtained to be 1.04 eV. It is indicated that the diamond Schottky barrier diode fabricated only by B ion implantation is improved by refinement of the electrode structure. The hole concentration was estimated to be 3.0 × 1017 cm−3 from the C-V measurements.

Optimization of Activation Annealing Condition for Boron‐Implanted Diamond

“…Details of the fitting process can be referred in the previous letter. [ 19 ] To estimate the ionization energy of dopants, we should best‐fit the theoretically estimated carrier concentration by Equation () to the experimentally obtained one with three fitting parameters of acceptor concentration ( N A ), compensation ratio ( K = N D / N A ), and ionization energy ( E A ). Particularly at the low carrier concentration limit …”

“…We then reluctantly estimate the ionization energy of these samples by Equation () as fitting parameters of A and E A in the mainly high‐temperature region of , in which the influence of hopping conduction will be neglected. [ 19,20 ] Here, the arbitrary parameter A was merely introduced to adjust the magnification of the vertical axis in the fitting process. The estimated ionization energy is summarized in Table 1.…”

“…[ 17,18 ] Recently, we investigated the electrical activation of heavily implanted B atoms with doping a concentration of 3.5 × 10 19 cm −3 in diamond focusing on the temperatures during the implantation and postannealing. [ 19,20 ] In the previous articles, the temperature in implantation was investigated in two extreme temperatures of room temperature (RT) and 900 °C, and that in activation annealing was done from 1150 to 1450 °C. As a result, we found the optimum temperatures of B implantation and postannealing for realizing effective electrical activation of implanted B: the implantation and activation annealing should be performed at RT and 1300 °C, respectively.…”