Abstract
To accurately analyze the deep states at the insulator/wide-bandgap semiconductor interface, this study reassessed and improved the conventional photoassisted capacitance-voltage (PACV) method. First, as previously pointed out, the illumination time under depletion should be long enough that the voltage shift caused by interface-state depopulation (in n-type semiconductors) saturates. Excessive illumination, however, causes insulator charging, thereby apparently increasing estimated values. To solve this problem, this study proposes to measure reference characteristics just after postillumination ones. Secondly, the postillumination measurements should be started without delay after turning off the light or may be carried out with the samples being illuminated. Thirdly, the depletion should be deep enough that the magnitude of band bending in the substrate at the beginning of the postillumination measurements is larger than 1 V. This guideline considerably relaxes a previous one that required a band bending of bandgap or larger. Furthermore, this study developed a method for compensating the interface-state depopulation (in n-type) during the reference measurements, in which the depopulation causes the so-called stretch-out. The results thus obtained from an Al/Al 2 O 3 /GaN capacitor agreed fairly well with those by a recently developed transient photoassisted capacitance method, supporting the validity of both methods. Being less sensitive to the gate-insulator charging, the advanced PACV method developed here has an advantage over the transient method and, therefore, will help advance the technology for fabricating high-performance, high-reliability insulator/wide-bandgap semiconductor insulators.
| Original language | English |
|---|---|
| Article number | 175704 |
| Journal | Journal of Applied Physics |
| Volume | 125 |
| Issue number | 17 |
| DOIs | |
| Publication status | Published - 2019 May 7 |
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ASJC Scopus subject areas
- Physics and Astronomy(all)
Cite this
Advanced photo-assisted capacitance-voltage characterization of insulator/wide-bandgap semiconductor interface using super-bandgap illumination. / Hiraiwa, Atsushi; Okubo, Satoshi; Horikawa, Kiyotaka; Kawarada, Hiroshi.
In: Journal of Applied Physics, Vol. 125, No. 17, 175704, 07.05.2019.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Advanced photo-assisted capacitance-voltage characterization of insulator/wide-bandgap semiconductor interface using super-bandgap illumination
AU - Hiraiwa, Atsushi
AU - Okubo, Satoshi
AU - Horikawa, Kiyotaka
AU - Kawarada, Hiroshi
PY - 2019/5/7
Y1 - 2019/5/7
N2 - To accurately analyze the deep states at the insulator/wide-bandgap semiconductor interface, this study reassessed and improved the conventional photoassisted capacitance-voltage (PACV) method. First, as previously pointed out, the illumination time under depletion should be long enough that the voltage shift caused by interface-state depopulation (in n-type semiconductors) saturates. Excessive illumination, however, causes insulator charging, thereby apparently increasing estimated values. To solve this problem, this study proposes to measure reference characteristics just after postillumination ones. Secondly, the postillumination measurements should be started without delay after turning off the light or may be carried out with the samples being illuminated. Thirdly, the depletion should be deep enough that the magnitude of band bending in the substrate at the beginning of the postillumination measurements is larger than 1 V. This guideline considerably relaxes a previous one that required a band bending of bandgap or larger. Furthermore, this study developed a method for compensating the interface-state depopulation (in n-type) during the reference measurements, in which the depopulation causes the so-called stretch-out. The results thus obtained from an Al/Al 2 O 3 /GaN capacitor agreed fairly well with those by a recently developed transient photoassisted capacitance method, supporting the validity of both methods. Being less sensitive to the gate-insulator charging, the advanced PACV method developed here has an advantage over the transient method and, therefore, will help advance the technology for fabricating high-performance, high-reliability insulator/wide-bandgap semiconductor insulators.
AB - To accurately analyze the deep states at the insulator/wide-bandgap semiconductor interface, this study reassessed and improved the conventional photoassisted capacitance-voltage (PACV) method. First, as previously pointed out, the illumination time under depletion should be long enough that the voltage shift caused by interface-state depopulation (in n-type semiconductors) saturates. Excessive illumination, however, causes insulator charging, thereby apparently increasing estimated values. To solve this problem, this study proposes to measure reference characteristics just after postillumination ones. Secondly, the postillumination measurements should be started without delay after turning off the light or may be carried out with the samples being illuminated. Thirdly, the depletion should be deep enough that the magnitude of band bending in the substrate at the beginning of the postillumination measurements is larger than 1 V. This guideline considerably relaxes a previous one that required a band bending of bandgap or larger. Furthermore, this study developed a method for compensating the interface-state depopulation (in n-type) during the reference measurements, in which the depopulation causes the so-called stretch-out. The results thus obtained from an Al/Al 2 O 3 /GaN capacitor agreed fairly well with those by a recently developed transient photoassisted capacitance method, supporting the validity of both methods. Being less sensitive to the gate-insulator charging, the advanced PACV method developed here has an advantage over the transient method and, therefore, will help advance the technology for fabricating high-performance, high-reliability insulator/wide-bandgap semiconductor insulators.
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U2 - 10.1063/1.5089793
DO - 10.1063/1.5089793
M3 - Article
AN - SCOPUS:85065258836
VL - 125
JO - Journal of Applied Physics
JF - Journal of Applied Physics
SN - 0021-8979
IS - 17
M1 - 175704
ER -