Evolution and Mechanism of P-GaN Films Under Proton Irradiation and Its Influence on Electronic Device

Electrical and optical properties deterioration of P-GaN films under 150 keV proton irradiation were investigated. Through the Hall measurement method, as the irradiation fluence increasing, the carrier concentration of P-GaN films decreases from 1.23
$\times \,\,10^{{17}}$
to
$-8.24\,\,\times \,\,10^{{16}}$
cm
⁻³
, and the carrier mobility change from 5.64 to 295.84 cm
²
/V/s. And through the circular transmission line model method, the sheet resistance and specific contact resistance for P-GaN films increased first and then decreased slightly under the proton irradiation. Radiation-induced
$\text{V}_{\mathrm {N}}$
,
$\text{Ga}_{\mathrm {i}}$
,
$\text{V}_{\mathrm {Ga}}$
, and
$\text{N}_{\mathrm {i}}$
were found to be responsible for the degradation of P-GaN films. It was confirmed that P-GaN has been transformed into N-GaN under the fluence of 1
$\times \,\,10^{15}$
p/cm
²
. The optical properties of the P-GaN films were characterized by examining changes in the photoluminescence spectrum. In addition, the electrical characteristics of Schottky barrier diode (SBD) and p-i-n diodes with the same structure (except for 0.5
$\mu \text{m}$
P-GaN of p-i-n diode) were used to study the effect of P-GaN degradation on electronic device performance. When P-GaN was transformed into N-GaN, p-i-n diodes lost the electrical characteristics of the p-n junction and the
${I}$
–
${V}$
curves of p-i-n diode are similar to that with SBD.