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1.
The authors describe the fabrication and characteristics of the first high-voltage (400-V) silicon-carbide (6H-SiC) Schottky barrier diodes. Measurements of the forward I -V characteristics of these diodes demonstrate a low forward voltage drop of ~1.1 V at an on-state current density of 100 A/cm2 for a temperature range of 25 to 200°C. The reverse I -V characteristics of these devices exhibit a sharp breakdown, with breakdown voltages exceeding 400 V at 25°C. In addition, these diodes are shown to have superior reverse recovery characteristics when compared with high-speed silicon P-i-N rectifiers 相似文献
2.
Hydrogen annealing at 700-1100°C for 0-300 s has been combined with SiO2 formation by rapid thermal processing (RTP). The SiO2 films formed with the above processes were evaluated by C -V and I -V measurements and by time-dependent dielectric breakdown (TDDB) tests. These films provide longer time to breakdown andless positive charge generation than SiO2 films formed without H 2 annealing. In particular, the SiO2 formation-H2 annealing SiO 2 formation process is quite effective in improving the dielectric strength of the thin RTP-SiO2 film 相似文献
3.
Low-voltage silicon trench power MOSFETs with forward conductivities approaching the silicon limit are reported. Vertical trench power MOSFETs with the measured performances of V DB =55 V (R sp=0.2 mΩ-cm2, k D=5.7 Ω-pF) and V DB=35 V (R sp=0.15 mΩ-cm2, k D =4.3 Ω-PF) were developed where V DB is the drain-source avalanche breakdown voltage, R sp is the specific on-state resistance, and k D=R spC sp is the input device technology factor where C sp is the specific MOS gate input capacitance. The optimum device performance resulted from an advanced trench processing technology that included (1) an improved RIE process to define scaled vertical silicon trenches, (2) silicon trench sidewall cleaning to reduce the surface damage, and (3) a novel polysilicon gate planarization technique using a sequential oxidation/oxide etchback, process. The measured performances are shown to be in excellent agreement with the two-dimensional device simulations and the calculated results obtained from an analytical model 相似文献
4.
Malik R.J. Chand N. Nagle J. Ryan R.W. Alavi K. Cho A.Y. 《Electron Device Letters, IEEE》1992,13(11):557-559
Temperature-dependent measurements from 25 to 125°C have been made of the DC I -V characteristics of HBTs with GaAs and In0.53Ga0.47As collector regions. It was found that the GaAs HBTs have very low output conductance and high collector breakdown voltage BV CEO>10 V at 25°C, which increases with temperature. In striking contrast, the In0.53Ga0.47As HBTs have very high output conductance and low BV CEO~2.5 V at 25°C, which actually decreases with temperature. This different behavior is explained by the >104 higher collector leakage current, I CO, in In0.53Ga0.47As compared to GaAs due to bandgap differences. It is also shown that device self-heating plays a role in the I -V characteristics 相似文献
5.
Effects of ultradry annealing on time-dependent dielectric breakdown (TDDB) lifetime (T TDDB) were investigated for Si MOS diodes with 5-nm-thick silicon oxide and P-doped polysilicon gate electrode films. This annealing was performed at 800°C in ultradry N2 of less than 1-ppm moisture concentration after the electrode formation. Under an accumulation-bias stress condition, T TDDB for the ultradry-annealed n-type Si diodes was larger than that for the conventionally annealed ones, while such T TDDB enhancement was not confirmed in the p-type ones. Since positive charges induced near anode-side oxide interfaces are closely related to T TDDB, the T TDDB enhancement for the ultradry-annealed n-type Si diodes probably reflects a qualitative improvement of the anode-side, i.e., gate-electrode-oxide, interfaces by ultradry annealing 相似文献
6.
Mimura A. Konishi N. Ono K. Ohwada J.-I. Hosokawa Y. Ono Y.A. Suzuki T. Miyata K. Kawakami H. 《Electron Devices, IEEE Transactions on》1989,36(2):351-359
High-performance poly-Si TFTs were fabricated by a low-temperature 600°C process utilizing hard glass substrates. To achieve low threshold voltage (V TH) and high field-effect mobility (μFE), the conditions for low-pressure chemical vapor deposition of the active layer poly-Si were optimized. Effective hydrogenation was studied using a multigate (maximum ten divisions) and thin-poly-Si-gate TFTs. The crystallinity of poly-Si after thermal annealing at 600°C depended strongly on the poly-Si deposition temperature and was maximum at 550-560°C. The V TH and μFE showed a minimum and a maximum, respectively, at that poly-Si deposition temperature. The TFTs with poly-Si deposited at 500°C and a 1000-Å gate had a V TH of 6.2 V and μFE of 37 cm2/V-s. The high-speed operation of an enhancement-enhancement type ring oscillator showed its applicability to logic circuits. The TFTs were successfully applied to 3.3-in.-diagonal LCDs with integration of scan and data drive circuits 相似文献
7.
Self-aligned high-frequency InP/InGaAs double heterojunction bipolar transistors (DHBTs) have been fabricated on a Si substrate. A current gain of 40 was obtained for a DHBT with an emitter dimension of 1.6 μm×19 μm. The S parameters were measured for various bias points. In the case of I C=15 mA, f T was 59 GHz at V CE=1.8 V, and f max was 69 GHz at V CE=2.3 V. Due to the InP collector, breakdown voltage was so high that a V CE of 3.8 V was applied for I C=7.5 mA in the S -parameter measurements to give an f T of 39 GHz and an f max of 52 GHz 相似文献
8.
p+-n junction diodes for sub-0.25-μm CMOS circuits were fabricated using focused ion beam (FIB) Ga implantation into n-Si (100) substrates with background doping of Nb=(5-10)×10 15 and Nb+=(1-10)×1017 cm-3. Implant energy was varied from 2 to 50 keV at doses ranging from 1×1013 to 1×1015 cm-2 with different scan speeds. Rapid thermal annealing (RTA) was performed at either 600 °C or 700°C for 30 s. Diodes fabricated on Nb+ with 10-keV Ga+ exhibited a leakage current (IR) 100× smaller than those fabricated with 50-keV Ga+. Tunneling was determined to be the major current transport mechanism for the diodes fabricated on Nb+ substrates. An optimal condition for I R on Nb+ substrates was obtained at 15 keV/1×1015 cm-2. Diodes annealed at 600°C were found to have an I R 1000× smaller than those annealed at 700°C. I -V characteristics of diodes fabricated on Nb substrates with low-energy Ga+ showed no implant energy dependence. I -V characteristics were also measured as a function of temperature from 25 to 200°C. For diodes implanted with 15-keV Ga +, the cross-over temperatures between I diff and I g-r occurred at 106°C for Nb + and at 91°C for Nb substrates 相似文献
9.
Hot-carrier stressing was carried out on 1-μm n-type MOSFETs at 77 K with fixed drain voltage V d=5.5 V and gate voltage V g varying from 1.5 to 6.5 V. It was found that the maximum transconductance degradation ΔG m and threshold voltage shift ΔV t, do not occur at the same V g. As well, ΔK t is very small for the V g <V d stress regime, becomes significant at V g≈V d, and then increases rapidly with increasing V g, whereas ΔG m has its maximum maximum in the region of maximum substrate current. The behavior is explained by the localized nature of induced defects, which is also responsible for a distortion of the transconductance curves and even a slight temporary increase in the transconductance during stress 相似文献
10.
Laskar J. Ketterson A.A. Baillargeon J.N. Brock T. Adesida I. Cheng K.Y. Kolodzey J. 《Electron Device Letters, IEEE》1989,10(12):528-530
The observation of negative differential resistance (NDR) and negative transconductance at high drain and gate fields in depletion-mode AlGaAs/InGaAs/GaAs MODFETs with gate lengths L g ~0.25 μm is discussed. It is shown that under high bias voltage conditions, V ds>2.5 V and V gs>0 V, the device drain current characteristic switches from a high current state to a low current state, resulting in reflection gain in the drain circuit of the MODFET. The decrease in the drain current of the device corresponds to a sudden increase in the gate current. It is shown that the device can be operated in two regions: (1) standard MODFET operation for V gs<0 V resulting in f max values of >120 GHz, and (2) a NDR region which yields operation as a reflection gain amplifier for V gs >0 V and V ds>2.5 V, resulting in 2 dB of reflection gain at 26.5 GHz. The NDR is attributed to the redistribution of charge and voltage in the channel caused by electrons crossing the heterobarrier under high-field conditions. The NDR gain regime, which is controllable by gate and drain voltages, is a new operating mode for MODFETs under high bias conditions 相似文献
11.
Hot-carrier stressing carried out as a function of substrate voltage on 2-μm NMOS devices under bias conditions V d =8 V and V g=5.5 V is discussed. The time power-law dependence of stressing changes as a function of substrate bias (V b), having a power-law gradient of 0.5 for V b=0 V and 0.3 for V b=-9 V. Investigation of the type of damage resulting from stressing shows that at V b=0 V, interface state generation results, while at V b=-9 V, the damage is mostly by charge trapping. Measurements of the gate current under these two substrate bias conditions show that the gate electron current increases by over two orders of magnitude upon application of a strong back bias. It is suggested that the electron trapping arises from this enhanced gate electron current under large substrate voltage conditions 相似文献
12.
A simplified analytical expression for the temperature dependent saturated I D-V D characteristics of hydrogenated amorphous silicon (a-Si:H) thin-film transistors, between -50°C and 90°C, is presented and experimentally verified. The results show that the experimental transfer and output characteristics at several temperatures are easily modeled by a single equation. The model is based on three functions obtained from the experimental data of I D versus V G, over a range of temperature. Theoretical results confirm the simple form of the model in terms of the device geometry. As the temperature increased, the saturated drain current increased and, at a fixed gate voltage the device saturated at increasingly larger drain voltages while the threshold voltage decreased. Good agreement between the measured data and the model was obtained up to 363 K. Also observed at temperatures larger than 363 K was a decrease in I D and more severe gate voltage hysteresis characteristics 相似文献
13.
Chen Y.-K. Temkin H. Tanbun-Ek T. Logan R.A. Nottenburg R.N. 《Electron Device Letters, IEEE》1989,10(4):162-164
Buried p-buffer double heterostructure modulation-doped field-effect transistors (BP DH-MODFETs) with an InGaAs quantum-well channel were fabricated with high transconductance and good breakdown voltage, by placing the metal gate directly on Fe-doped InP insulating layer. Excellent extrinsic DC transconductance of 560 mS/mm and a high gate-to-drain diode breakdown voltage (greater than 20 V) were achieved at room temperature with FETs of 1.2-μm gate length. Unity currently gain cutoff frequency f T of 24 GHz and maximum oscillation frequency f max of 60 GHz were demonstrated for a drain to source voltage V DS=4 V, which corresponds to an average electron velocity of 2.2×107 cm/s in the quantum well 相似文献
14.
The authors present a theoretical model of power p+-n-n + diodes with a graded-gap base and either homojunctions (GB) or heterojunctions (HGB), and numerical calculations of static and dynamic characteristics of AlGaAs (GaAsP) based structures. It is shown that HGB diodes will exhibit characteristics and properties significantly better than those of simple (homojunctions plus uniform base) GaAs and Si diodes. For example, the forward voltage drop in a high-voltage (W /L p=13) high-frequency (t rr=25 ns) HGB diode will be 50% and 300% smaller than the drop in, respectively, simple GaAs and Si diodes with the same W /L p and t rr. Other significant projected improvements include operation up to 450°C, an order of magnitude reduction in the reverse current, and a 50% increase in the breakdown voltage 相似文献
15.
Lu C.-Y. Sung J.M. Kirsch H.C. Hillenius S.J. Smith T.E. Manchanda L. 《Electron Device Letters, IEEE》1989,10(5):192-194
The C -V characteristics of arsenic-doped polysilicon show a gate-bias dependence of the inversion capacitance and a reduction in the expected value of the inversion capacitance. The characteristics have been investigated with quasistatic and high-frequency C -V as well as conductance measurements of various capacitors that have been subjected to annealing times and temperatures ranging from 900°C/30 min to rapid thermal annealing at 1050°C. The results can be explained by assuming that there is a depletion region forming in the polysilicon due to insufficient activation of the dopant at the polysilicon/oxide surface. The impact of this condition on the device characteristics is shown to be a 20-30% reduction in the G m of NMOS transistors with 125-Å Gate oxide thickness 相似文献
16.
The device consists primarily of several molecular-beam-epitaxy (MBE-) grown GaAs/(AlGa)As resonant tunneling diodes connected in parallel. This device exhibits multiple peaks in the I -V characteristic. When a load resistor is connected, the circuit can be operated in a multiple stable mode. With this concept, implementation of three-state and four-state memory cells are made. In the three-state case the operating points at voltages V 0=0.27 V , V 1=0.42 V, and V 2=0.53 V represent the logic levels 0, 1, and 2. Similarly for the four-state memory cell the logic levels voltages are V 0=0.35 V, V 1=0.42 V, V 2=0.54 V, and V 3=0.59 V. A suggestion of an integrated device structure using this concept is also presented 相似文献
17.
N-channel MOSFETs with different gate dielectrics, such as silicon dioxide, silicon dioxide annealed in nitrous oxide (NO), and reoxidized nitrided oxide (ONO), were first hot-carrier (HC) stressed and then irradiated to a total dose of 1.5 Mrd. For equal substrate current stressing NO devices have the least degradation, whereas the threshold voltage (V t) shift due to irradiation is maximum for these devices. For all three types of gate dielectrics the V t shift due to irradiation of HC stressed devices was higher than that of the unstressed device. However, for ONO devices the V t shift due to irradiation of the hot-electron stressed (stressing with V d=V g=6.5 V) device was less than that of the unstressed device 相似文献
18.
《Electron Devices, IEEE Transactions on》1990,37(1):153-158
The fabrication of a silicon heterojunction microwave bipolar transistor with an n+ a-Si:H emitter is discussed, and experimental results are given. The device provides a base sheet resistance of 2 kΩ/□ a base width 0.1 μm, a maximum current gain of 21 (V CE=6 V, I c=15 mA), and an emitter Gummel number G E of about 1.4×1014 Scm-4. From the measured S parameters, a cutoff frequency f t of 5.5 GHz and maximum oscillating frequency f max of 7.5 GHz at V CE=10 V, I c=10 mA are obtained 相似文献
19.
The circuit performance of CMOS technologies with silicon dioxide (SiO2) and reoxidized nitrided oxide (RONO) gate dielectrics over the normal regime of digital circuit operation, i.e. V GS⩽5 V and B DS⩽5 V, is discussed. The simulation of a simple CMOS inverter has shown that the SiO2 inverter consistently outperforms the RONO inverter over temperatures ranging from 300 to 100 K. This can be attributed mainly to the significantly lower μp (hole mobility) of RONO p-channel devices. At 300 K, μp(RONO) is 14-8% smaller than μp(SiO2) over the entire range of gate biases, while μn(RONO) (electron mobility of n-channel RONO devices) is also smaller than μn(SiO2) and reaches only 96% of μn(SiO2) at V GS=5 V. At 100 K, μn(RONO)/μn (SiO2) at V GS=5 V is increased to 1.10, however, μp(RONO)/μp(SiO2) at V GS=5 V is degraded to 0.59. The dependence of circuit performance on the supply voltage has also been evaluated for the RONO and SiO2 inverters 相似文献
20.
Self-heating effects in basic semiconductor structures 总被引:2,自引:0,他引:2
Amerasekera A. Chang M.-C. Seitchik J.A. Chatterjee A. Mayaram K. Chern J.-H. 《Electron Devices, IEEE Transactions on》1993,40(10):1836-1844
Investigates the effects of self-heating on the high current I -V characteristics of semiconductor structures using a fully coupled electrothermal device simulator. It is shown that the breakdown in both resistors and diodes is caused by conductivity modulation due to minority carrier generation. In isothermal simulations with T =300 K, avalanche generation is the source of minority carriers. In simulations with self-heating, both avalanche and thermal generation of minority carriers can contribute to the breakdown mechanism. The voltage and current at breakdown are dependent on the structure of the device and the doping concentration in the region with lower doping. For all structures, except highly doped resistors with poor heating sinking at the contacts, the temperature at thermal breakdown ranged from 1.25T i to 3T i , where T i is the temperature at which the semiconductor goes intrinsic. Hence, it is found that T =Ti is not a general condition for thermal (or second) breakdown. From these studies, an improved condition for thermal breakdown is proposed 相似文献