Observation of Side-Gating Effect in AlGaN/GaN Heterostructure Field Effect Transistors
The side-gating effect was demonstrated in AlGaN/GaN heterostructure field effect transistors (HFETs) for the first time. Using 10-μm-thick i-GaN buffer layers, drain currents decreased significantly with the application of a negative bias on a side gate 8 μm away from the FET. The transient respons...
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| Published in: | Japanese Journal of Applied Physics Vol. 52; no. 8; pp. 08JN28 - 08JN28-5 |
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| Main Authors: | , , , |
| Format: | Journal Article |
| Language: | English |
| Published: |
The Japan Society of Applied Physics
01-08-2013
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| Subjects: | |
| Online Access: | Get full text |
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| Summary: | The side-gating effect was demonstrated in AlGaN/GaN heterostructure field effect transistors (HFETs) for the first time. Using 10-μm-thick i-GaN buffer layers, drain currents decreased significantly with the application of a negative bias on a side gate 8 μm away from the FET. The transient responses with LED illumination demonstrated half-recovery condition that can be interpreted as a negative-charge redistribution through a hole emission from traps. The application of a positive side-gate bias confirmed the half-recovery mechanism. From the temperature variation measurements, the trap energy level is estimated to be 0.76 eV from the valence band with a hole capture cross section of approximately $4\times 10^{-16}$ cm 2 . All these results indicate that the side-gating effect is caused by hole traps in the i-GaN layer, which is in accord with the Shockley--Read--Hall model of deep traps. |
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| Bibliography: | (Color online) Epitaxial layer structures used in experiments. (a) Sample (A) and (b) sample (B). (Color online) Schematic cross section of the device structure for the side-gating effect measurement. (Color online) Pattern layout of the side-gating effect measurement devices. (Color online) $V_{\text{D}}$--$I_{\text{D}}$ characteristics at $V_{\text{G}} = 0$ V under side-gate bias application. (a) Sample (A) and (b) sample (B). (Color online) $I_{\text{D}}$ and $I_{\text{SG}}$ versus $V_{\text{SG}}$ characteristics of the sample (B). $V_{\text{G}} = 0$ V and $V_{\text{D}} = 4$ V. (Color online) Drain current responses by side-gate bias change at $V_{\text{G}} = 0$ V and $V_{\text{D}} = 1$ V. (a) Sample (A) and (b) sample (B). Black lines are those measured in the dark. Red dashed lines are the drain current with LED lights. (Color online) Drain current responses of sample (B) at different temperatures. $V_{\text{G}} = 0$ V, $V_{\text{D}} = 1$ V, and $V_{\text{SG}}$ was varied from 0 to $-20$ V. (Color online) One-dimensional simulation of n--i--n structure. (a) Simulation structure, where $N_{\text{SA}} = 1\times 10^{17}$ cm -3 , $N_{\text{DD}} = 2\times 10^{17}$ cm -3 , $\sigma_{\text{N}} = \sigma_{\text{P}} = 1\times 10^{-12}$ cm 2 , $E_{\text{T}} = 2.4$ eV from $E_{\text{C}}$. (b) Potential profiles during the stress-on process ($V_{\text{ANODE}} = 0\rightarrow 50$ V, corresponding to $V_{\text{SG}} = 0\rightarrow -50$ V). (c) Recovery process ($V_{\text{ANODE}} = 50\rightarrow 0$ V, corresponding to $V_{\text{SG}} = -50\rightarrow 0$ V). (d) Transients of the conduction band energy at the sample center indicated by the vertical lines in (b) and (c). (Color online) Drain current responses of sample (B) for both positive- and negative-side-gate-bias cases. The side-gate biases were applied from 60 to 2060 s. (Color online) Model explaining the trap charge variation in the side-gating effect. (a) Stress-on case. (b) Recovery case. ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
| ISSN: | 0021-4922 1347-4065 |
| DOI: | 10.7567/JJAP.52.08JN28 |