| 1. |
|
|
| 2. |
- Allerstam, Fredrik, 1978, et al.
(författare)
-
Comparison between oxidation processes used to obtain the high inversion channel mobility in 4H-SiC MOSFETs
- 2007
-
Ingår i: Semiconductor Science and Technology. - : IOP Publishing. - 1361-6641 .- 0268-1242. ; 22:4, s. 307-311
-
Tidskriftsartikel (refereegranskat)abstract
- In this work two oxidation methods aimed at improving the silicon face 4H-SiC/SiO 2 interface are compared. One is an oxidation in N 2 O performed in a quartz tube using quartz sample holders and the other is a dry oxidation performed in an alumina tube using alumina sample holders. In n-type metal oxide semiconductor (MOS) capacitors the interface state density near the SiC conduction band edge is estimated using capacitance-voltage (C-V) and thermal dielectric relaxation current (TDRC) measurements. N-channel metal oxide semiconductor field effect transistors (MOSFETs) are characterized by current-voltage (I-V) techniques and the inversion channel mobility is extracted. It is shown that the high inversion channel mobility (154 cm 2 V -1 s -1 ) seen in samples oxidized using alumina correlates with a low interface trap density (3.6 × 10 11 cm -2 ). In the case of N 2 O oxidation the mobility is lower (24 cm 2 V -1 s -1 ) and the interface trap density is higher (1.6 × 10 12 cm -2 ). Room temperature C-V measurements are of limited use when studying traps near the conduction band edge in MOS structures while the TDRC measurement technique gives a better estimate of their density. © 2007 IOP Publishing Ltd.
|
|
| 3. |
- Allerstam, Fredrik, 1978, et al.
(författare)
-
Formation of deep traps at the 4H-SiC/SiO2 interface when utilizing sodium enhanced oxidation
- 2007
-
Ingår i: Materials Science Forum. - 1662-9752 .- 0255-5476. ; 556-557, s. 517-520
-
Konferensbidrag (refereegranskat)abstract
- This paper reports studies of deep acceptor-type interface traps at the 4H-SiC/SiO2 interface. These traps are created during sodium enhanced oxidation of Si-terminated 4H-SiC. The trap concentration is above 3×1012 cm-2 and their activation energy is larger than 0.8 eV.
|
|
| 4. |
|
|
| 5. |
- Gudjonsson, Gudjon, 1973, et al.
(författare)
-
Design and Fabrication of 4H-SiC RF MOSFETs
- 2007
-
Ingår i: IEEE Transactions on Electron Devices. - 1557-9646 .- 0018-9383. ; 54:12, s. 3138-3145
-
Tidskriftsartikel (refereegranskat)abstract
- We present simulations, fabrication and analysis of 4H-SiC RF power MOSFETs. We obtain an extrinsic transition frequency of 11.2 GHz and an f max = 11.9 GHz, a breakdown voltage above 200 V and an output power of 1.9 W/mm at 3 GHz. The measured devices are double fingered, source-gate-draingate-source with 2 × 0.4 mm total gate width and the nominal channel length of the devices is 0.5 μm. To the authors knowledge, this is the highest transition frequency and output power density ever reported for SiC RF MOSFETs. The antipunchthrough is introduced as a way to take advantage of the SiC's material properties. A detailed description of the device processing is also given. © 2007 IEEE.
|
|
| 6. |
|
|
| 7. |
- Gudjonsson, Gudjon, 1973
(författare)
-
Design and Fabrication of Silicon Carbide RF MOSFET for L- and S-band applications
- 2006
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis describes realisation of 4H-SiC radio-frequency metal-oxide-semiconductor field effect transistors (RF MOSFETs). Such transistors are in principle very attractive devices for high power and high frequency electronics. They are intended as a direct replacement for their silicon counterparts, offering higher power. In order to enable high frequency operation together with high voltage handling capability the concept of buried anti-punch-through (APT) is introduced and implemented in RF devices. The buried APT prevents punch-through of the channel region without seriously affecting the inversion channel mobility and the threshold voltage of the transistor. 4H-SiC RF MOSFET with output power density of 1.9W/mm at 3GHz from a 0.8mm device is demonstrated. This is twice the output power density from Si MOSFETs. Previously, insufficient quality of the silicon dioxide/4H-SiC interface has resulted in very low inversion channel mobility (10-40cm2/Vs) in such devices and unacceptable current output and frequency response. Major improvements in channel mobility and current capacity are reported in this thesis. These results make feasible fabrication of high frequency SiC MOSFETs. Transistors with peak field effect mobility above 150cm2/Vs are demonstrated. Furthermore, MOSFETs with aluminium ion implanted gate channels are investigated. In contrast to previous reports, high quality SiO2/SiC interface is obtained both when the gate oxide is grown on p-type epitaxial material and when grown on ion implanted regions. The mobility reduction with increasing acceptor density follows the same functional relation as in n-channel Si MOSFETs.
|
|
| 8. |
|
|
| 9. |
|
|
| 10. |
|
|
