學術出版;;Publications

Permanent URI for this communityhdl:11536/1

收集所有交通大學研究人員與學生個人或團體所發表之各項學術著作，涵蓋期刊論文、教師專書、學位論文等項。;;Collections of Publications of NCTU Researchers and Students Like Journal Papers and Thesis.

Browse

🏛️國立陽明交通大學機構典藏

Search Results

Now showing 1 - 10 of 59

2-V-operation delta-doped power HEMT's for personal handy-phone systems
(1997-08-01)
Lai, YL
;
Chang, EY
;
Chang, CY
;
Liu, TH
;
Wang, SP
A high-efficiency and high-power-density delta-doped AIGaAs/InGaAs HEMT with low adjacent channel leakage has been developed for the digital wireless personal handy-phone system (PHS). When qualified by 1.9-GHz pi/4-shifted quadrature phase shift keying (QPSK) modulated PHS standard signals, the 2.0-V-operation HEMT with a 1-mm gate width demonstrated a power-added efficiency of 45.3% and an output power density of 105 mW/mm. This is the highest power density ever reported by the power transistors for the PHS. The state-of-the-art results for the PHS operating at 2.0 V were achieved by the delta-doped power HEMT for the first time.
5 mm high-power-density dual-delta-doped power HEMT's for 3 V L-band applications
(1996-05-01)
Lai, YL
;
Chang, EY
;
Chang, CY
;
Chen, TK
;
Liu, TH
A high-power-density dual-delta-doped AlGaAs/InGaAs/GaAs high electron mobility transistor (HEMT) for personal communication applications has been developed. A 5.0 mm gate-width device operating at a drain bias of 3.0 V gave an output power over 1 W, The 1 mu m gate-length HEMT exhibited a current density of 425 mA/mm at V-gs = 0.5 V, The maximum transconductance of the device was 270 mS/mm, The effective knee voltage was as low as 0.3 V, At the class AB operation, the HEMT demonstrated an output power density of 200 mW/mm, 64% power-added efficiency and 18.2 dB linear gain at 900 MHz, This is the highest power density of a dual-delta-doped AlGaAs/InGaAs/GaAs HEMT reported to date for low voltage (3 V) wireless applications.
Reactive ion etching of GaN with BCl3/SF6 plasmas
(1996-07-01)
Feng, MS
;
Guo, JD
;
Lu, YM
;
Chang, EY
;
材料科學與工程學系
Reactive ion etching (RIE) with BCl3/SF6 plasmas of high quality GaN films grown by low pressure metallorganic chemical vapor deposition (LP-MOCVD) is reported. A high etch rate of 2100 Angstrom min(-1) was achieved with BCl3/SF6 plasmas at gas pressure 40 mtorr, total gas flow rate 40 seem, and radio-frequency (RF) power 300 W. The parameters affecting the etch rates such as BCl3/SF6 flow ratio, total gas pressure, RF power and self-bias voltage have been studied. Results indicate that under high RF power (300 W) the radical concentration is an etch rate-limiting factor at lower BCl3/SF6 pressure (lower than 40 mtorr), while self-bias voltage (ion bombardment) is a rate-limiting factor at higher pressure (more than 40 mtorr). Under lower RF power (150 W), self-bias voltage becomes the dominant factor of etch rate. Scanning electron microscopy (SEM) shows that the etched profile is highly anisotropic, and the etched area has some columnar residues due to Al compound contamination from the Al cathode during RIE.
A novel fabrication technique of T-shaped gates using an EGMEA and PMIPK multilayer resist system and a single-step electron-beam exposure
(1998-03-01)
Lai, YL
;
Lai, YK
;
Chang, CY
;
Chang, EY
;
材料科學與工程學系
A novel fabrication process of submicron T-shaped gates using an EGMEA and PMIPK multi-layer resist system and e-beam lithography has been developed. Due to the different sensitivities of the EGMEA and PMIPK resists, narrow/wide/narrow resist opening was obtained. The status of the electron scattering and the incident primary electron beams statistically construct the absorbed energy density distribution contours. The absorbed energy density distribution contours in association with the sensitivity feature of the resists and the appropriate development conditions determine the final resist profile. Only a single exposure step and a single development step are required. The simplified fabrication process of T-shaped gates significantly reduces not only the process time but also the production costs. The simple submicron T-shaped gate fabrication process studied provides a suitable technique for the mass manufacture of the advanced InP-based and GaAs-based microwave devices and circuits.
Power PHEMT with compact device layout for low voltage CDMA application
(2000-03-16)
Chang, EY
;
Lee, DH
;
Chen, SH
;
Chang, HC
;
材料科學與工程學系
A high efficiency low voltage operation dual delta-doped AlGaAs/ InGaAs/GaAs pseudomorphic high electron mobility transistor (PHEMT) for low voltage code division multiple access (CDMA) application has been developed. When tested at 2.4V and 1.9GHz under IS-95 CDMA modulation, the 20.16mm PHEMT device was found to have a linear output power of 28dBm with a power added efficiency of 30.2%. The device also has a saturation power of 30.0dBm with a power added efficiency of 61.5%. The high efficiency and linearity of the PHEMT at low bias voltage is attributed to the use of the dual delta-doped PHEMT structure and to the reduction of the size of the device layout. The device is suitable for low voltage CDMA applications.
Highly selective GaAs/Al0.2Ga0.8As wet etch process for the gate recess of low-voltage-power pseudomorphic high-electron-mobility transistor
(2000-08-01)
Chang, HC
;
Chang, EY
;
Chung, CC
;
Kuo, CT
;
材料科學與工程學系
A selective wet etch process for the gate recess of the GaAs power pseudomorphic high-electron-mobility transistors (pHEMT's) was developed. The power pHEMT's used in this study were epitaxially grown power Al0.2Ga0.8As/In0.2Ga0.8As pHEMT's with a 250 Angstrom GaAs cap layer and a 300 Angstrom Al0.2Ga0.8As electron-donating layer. The electron-donating layer was used as the etch-stop layer for the gate recess. A selectivity of 3400 : 1 was achieved for GaAs/Al0.2Ga0.8As layers using citric acid/tripotassium citrate/hydrogen peroxide etching solutions in this study. This is the highest selectivity for GaAs/AlxGa1-xAs selective etching reported so far. The pHEMT's processed using this selective etching demonstrated good device power performance, and the wet recess process did not cause any contamination or damage to the device. The test data indicates that this selective etch process can be of practical use for forming the gate recess of the power pHEMT's with good device performance and excellent electrical uniformity.
A 1.2-V operation power pseudomorphic high electron mobility transistor for personal handy phone handset application
(2000-10-15)
Chang, EY
;
Lee, DH
;
Chen, SH
;
材料科學與工程學系
;
Department of Materials Science and Engineering
A 1.2 V GaAs power pseudomorphic high electron mobility transistors (PHEMT's) for personal handy phone system (PHS) handset application was developed. The power PHEMT has a dual delta doped AlGaAs/InGaAs/GaAs based structure with compact device layout. The 6.72 mm device exhibits maximum power added efficiency (PAE) of 43.62% at 1.2V drain bias with an output power of 22.18 dBm. Under 1.9 GHz pi /4-shifted quadrature phase shift keying (QPSK) modulated PHS signal, the device shows an adjacent channel leakage power (P-adj) Of -56.86 dBc at 600 kHz apart from the center frequency and a linear efficiency of 41.31%. This is the first report on the 1.2-V operation power PHEMT for PHS handset application so far.
Thermal stability of Cu/Ta/GaAs multilayers
(2000-11-20)
Chen, CY
;
Chang, L
;
Chang, EY
;
Chen, SH
;
Chang, DF
Copper metallization for GaAs was evaluated by using Cu/Ta/GaAs multilayers for its thermal stability. A thin Ta layer of 40 nm was sputtered on the GaAs substrate as the diffusion barrier before copper film metallization. As judged from sheet resistance, x-ray diffraction, Auger electron spectroscopy and transmission electron microscopy, the Cu/Ta films with GaAs were very stable up to 500 degreesC without migration into GaAs. After 550 degreesC annealing, the interfacial mixing of Ta with GaAs substrate occurred, resulting in the formation of TaAs2. At 600 degreesC annealing, the reaction GaAs with Ta and Cu formed TaAs, TaAs2, and Cu3Ga, resulting from Cu migration and interfacial instability. (C) 2000 American Institute of Physics. [S0003-6951(00)03047-3].
A GaAs/AlAs wet selective etch process for the gate recess of GaAs power metal-semiconductor field-effect transistors
(2001-01-01)
Chang, EY
;
Lai, YL
;
Lee, YS
;
Chen, SH
;
材料科學與工程學系
A highly selective wet chemical etch process for gate recess of the GaAs power metal-semiconductor field effect transistors (MES FETs) was developed. The power MESFETs used in this study were epitaxially grown devices with a 20 Angstrom A1As etch-stop layer for gate recess. The selective etch process using citric acid/potassium citrate/hydrogen peroxide solution was studied. A selectivity better than 3800:1 was achieved for GaAs/A1As layers. This selective etch was applied both to high-power, high-voltage power MESFETs and low-voltage large-periphery power MESFETs. For high-power applications, the 14.7 mm device had a breakdown voltage of 22 V. When tested at 1.88 GHz with a drain bias of 10 V, it provided a maximum output power of 38.8 dBm and a maximum power-added efficiency of 52.5%. For low-voltage applications, the 19.8 mm device was tested under IS-95 code-division multiple access (CDMA) modulation at 1.88 GHz with a drain bias of 3.5 V. Under CDMA modulation, the device showed an output power of 28.03 dBm with an adjacent channel power rejection of -29.6 dBc at 1.25 MHz offset frequency. Both devices also showed excellent uniformity in pinch-off voltages. (C) 2000 The Electrochemical Society. S0013-4651 (00)03-053-6. All rights reserved.
Backside copper metallization of GaAs MESFETs using TaN as the diffusion barrier
(2001-06-01)
Chen, CY
;
Chang, EY
;
Chang, L
;
Chen, SH
;
材料科學與工程學系
Backside copper metallization of GaAs MESFETs using TaN as the diffusion barrier was studied. A thin TaN layer of 40 nm was sputtered on the GaAs substrate before copper firm metallization. As judged from the data of X-ray diffraction (XRD), Anger electron spectroscopy (AES), and cross-sectional transmission electron microscopy (TEM), the Cu/TaN films with GaAs were very stable without interfacial interaction up to 550 OC annealing, The copper metallized MESFETs were thermally stressed at 300 degreesC, The devices showed very little change in the device characteristics (<3 %) after thermal stress, and the changes of the electrical parameters and RF characteristics of the devices after thermal stress were of the same order as those devices without Cu metallization, These results show that TaN is a good diffusion barrier for Cu in GaAs devices and the Cu/TaN films can be used for the backside copper metallization of GaAs MESFETs.

學術出版;;Publications

Browse

Filters

Settings

Sort By

Results per page

🏛️國立陽明交通大學機構典藏

Search Results