TY - JOUR
T1 - Post-annealing processes to improve inhomogeneity of Schottky barrier height in Ti/Al 4H-SiC Schottky barrier diode
AU - Kyoung, Sinsu
AU - Jung, Eun Sik
AU - Sung, Man Young
N1 - Funding Information:
This work was supported by the Korea University Grant and the Technology Innovation Program , 10053797 , Development of low-power high-capacity Inverter modules and authentication technologies with a SiC SBD for LEV driving funded By the Ministry of Trade, Industry and Energy (MI, Korea).
Publisher Copyright:
© 2016 Elsevier B.V. All rights reserved.
PY - 2016/3/25
Y1 - 2016/3/25
N2 - To improve the high resistance and low breakdown voltage (BV) of a 4H-SiC Schottky barrier diode (SBD), the metal annealing process is conventionally used; this process stabilizes the Schottky barrier height (SBH). In this paper, we apply a post-metal annealing process to 4H-SiC Ti-SBD chips and verify the effect of the changes on electrical characteristics based on the post-annealing process. The results of experiments show that the condition of 873 K/30 min annealing created a stable SBH and a low value of on-resistance (Ron), which improved inhomogeneity. Based on the results of EDX and TEM analysis, the cause of improved SBH at the condition of 30 min was attributed to the generation of TiSix (which has a higher SBH than Ti). On the other hand, the improved value of Ron at the condition of 30 min was attributed to the change to γ-phase Ti3Al (which has a low resistance because diffused Al is present) caused by proper annealing. However, when more heat is applied in the cases of 773 K/60 min and 873 K/60 min, Ron increased and the SBH decreased. The results of EDX and TEM analysis showed that the low SBH was caused by Al spiking, which created an Al Schottky junction with a lower SBH than that of the Ti Schottky junction. Higher Ron resulted from the change to α-TiAl phase at the Al-Ti interface layer because of excessive diffusion of Ti and Al, which is due to the overly applied heat. From the results produced by this work, we can enhance the Al-Ti 4H-SiC SBD electrical characteristics by applying a suitable post-annealing process.
AB - To improve the high resistance and low breakdown voltage (BV) of a 4H-SiC Schottky barrier diode (SBD), the metal annealing process is conventionally used; this process stabilizes the Schottky barrier height (SBH). In this paper, we apply a post-metal annealing process to 4H-SiC Ti-SBD chips and verify the effect of the changes on electrical characteristics based on the post-annealing process. The results of experiments show that the condition of 873 K/30 min annealing created a stable SBH and a low value of on-resistance (Ron), which improved inhomogeneity. Based on the results of EDX and TEM analysis, the cause of improved SBH at the condition of 30 min was attributed to the generation of TiSix (which has a higher SBH than Ti). On the other hand, the improved value of Ron at the condition of 30 min was attributed to the change to γ-phase Ti3Al (which has a low resistance because diffused Al is present) caused by proper annealing. However, when more heat is applied in the cases of 773 K/60 min and 873 K/60 min, Ron increased and the SBH decreased. The results of EDX and TEM analysis showed that the low SBH was caused by Al spiking, which created an Al Schottky junction with a lower SBH than that of the Ti Schottky junction. Higher Ron resulted from the change to α-TiAl phase at the Al-Ti interface layer because of excessive diffusion of Ti and Al, which is due to the overly applied heat. From the results produced by this work, we can enhance the Al-Ti 4H-SiC SBD electrical characteristics by applying a suitable post-annealing process.
KW - 4H-SiC Schottky barrier diode
KW - Diffusion
KW - Inhomogeneity
KW - Post-annealing
KW - Schottky barrier height
KW - Transformation
UR - http://www.scopus.com/inward/record.url?scp=84957598138&partnerID=8YFLogxK
U2 - 10.1016/j.mee.2016.01.013
DO - 10.1016/j.mee.2016.01.013
M3 - Article
AN - SCOPUS:84957598138
SN - 0167-9317
VL - 154
SP - 69
EP - 73
JO - Microelectronic Engineering
JF - Microelectronic Engineering
ER -