Experimental Investigations on Ballistic Transport in Multi-Bridged Channel Field Effect Transistors
Electrical characteristics of multi bridged channel field effect transistor (MBCFET) with various channel lengths ($L$) ranging from 500 to 48 nm have been investigated. The current--voltage characteristics do not show any sign of short channel effect due to surrounding gate structures. The gate bia...
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| Published in | Japanese Journal of Applied Physics Vol. 50; no. 4; pp. 04DC18 - 04DC18-4 |
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| Main Authors | , , , , , , , |
| Format | Journal Article |
| Language | English |
| Published |
The Japan Society of Applied Physics
01.04.2011
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| Online Access | Get full text |
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| Summary: | Electrical characteristics of multi bridged channel field effect transistor (MBCFET) with various channel lengths ($L$) ranging from 500 to 48 nm have been investigated. The current--voltage characteristics do not show any sign of short channel effect due to surrounding gate structures. The gate bias power law of the drain saturation current, mobility, and ballistic efficiency as functions of $L$ show mixed features of drift-diffusion and ballistic transport. The channel resistance shows anomalous decrease when $L\leq 60$ nm, which is related with the transconductance overshoot resulted in ballistic transport at small $V_{\text{DS}}$. Temperature ($T$) dependence of the 100 nm device shows another type of transport region when $T < 40$ K, which can be interpreted as the one-dimensional quantum ballistic regime. |
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| Bibliography: | Schematic diagram of the fabrication process using standard complementary metal oxide semiconductor processes. (a) Si/SiGe selective growth. (b) Channel define using dummy oxide. (c) Source/drain extension selective growth and implantation. (d) Source/drain electrode deposition. (e) Channel implantation using SiN mask. (f) SiGe selective etch. (g) Gate oxidation. (h) Gate electrode deposition. (i) SEM image of fabricated device. (j) Electron current path. (a) $I_{\text{DS}}$--$V_{\text{GS}}$ and (b) $I_{\text{DS}}$--$V_{\text{DS}}$ characteristics measured from the device with $L = 48$ nm. (a) $I_{\text{Dsat}}$ vs ($V_{\text{GS}}$--$V_{\text{T}}$) obtained from seven devices with $L$ ranging from 48 to 500 nm (open symbols). The solid line denote the fitting results using $I_{\text{Dsat}} \sim (V_{\text{GS}}-V_{\text{T}})^{\alpha}$. (b) Extracted $\alpha$ as a function of $L$. (a) $\mu$ extracted from the devices of Fig. (closed circle) and calculated $\mu_{\text{eff}}$ (blue line) as a function of $L$. (b) Extracted $B$ as a function of $L$. (a) $I_{\text{DS}}$--$V_{\text{DS}}$ characteristics measured from the devices of Fig. when $V_{\text{GS}}-V_{\text{T}}$ is fixed at 100 mV. (b) $R_{\text{CH}}$ calculated from (a) as a function of $L$. The inset shows $dI_{\text{DS}}/dV_{\text{DS}}$ of the $L = 48$ nm device vs $V_{\text{DS}}$ near $V_{\text{DS}} = 0$. (c) $g_{\text{m}}$--$V_{\text{GS}}$ characteristics with $L$ ranging from 48 to 500 nm. (a) $I_{\text{DS}}$--$V_{\text{GS}}$ and (b) $I_{\text{DS}}$--$V_{\text{DS}}$ characteristics of the $L = 100$ nm device at various $T$ ranging from 300 to 4 K. (c) Extracted $R_{\text{CH}}$ as a function of $T$. (d) Extracted $\alpha$ as a function of $T$. |
| ISSN: | 0021-4922 1347-4065 |
| DOI: | 10.1143/JJAP.50.04DC18 |