The Variation of Schottky Barrier Height Induced by the Phase Separation of InAlAs Layers on InP HEMT Devices
oleh: Sang-Tae Lee, Minwoo Kong, Hyunchul Jang, Chang-Hun Song, Shinkeun Kim, Do-Young Yun, Hyeon-seok Jeong, Dae-Hyun Kim, Chan-Soo Shin, Kwang-Seok Seo
| Format: | Article |
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| Diterbitkan: | MDPI AG 2022-07-01 |
Deskripsi
We investigated the effect of phase separation on the Schottky barrier height (SBH) of InAlAs layers grown by metal–organic chemical vapor deposition. The phase separation into the In-rich InAlAs column and Al-rich InAlAs column of In<sub>0.52</sub>Al<sub>0.48</sub>As layers was observed when we grew them at a relatively low temperature of below 600 °C. From the photoluminescence spectrum investigation, we found that the band-gap energy decreased from 1.48 eV for a homogeneous In<sub>0.52</sub>Al<sub>0.48</sub>As sample to 1.19 eV for a phase-separated In<sub>x</sub>Al<sub>1−x</sub>As sample due to the band-gap lowering effect by In-rich In<sub>x</sub>Al<sub>1−x</sub>As (x > 0.7) region. From the current density–voltage analysis of the InAlAs Schottky diode, it was confirmed that the phase-separated InAlAs layers showed a lower SBH value of about 240 meV than for the normal InAlAs layers. The reduction in SBH arising from the phase separation of InAlAs layers resulted in the larger leakage current in InAlAs Schottky diodes.