1.5-W CW S-band GaInP/GaAs/GaInP double heterojunction bipolartransistor

We report the first large-signal power result from a double heterojunction bipolar transistor (DHBT) based on the GaInP/GaAs/GaInP material system. A CW output power of 1.51 W and a power added efficiency of 52% were achieved at 3 GHz. Because the GaInP collector has a relatively high bandgap of 1.89 eV, high DC bias voltage operation with collector bias extending to 20 V (for a 40-V swing) is possible in this GaInP/GaAs/GaInP DHBT. This high DC bias voltage operation represents a unique advantage over the more conventional AlGaAs/GaAs HBT     

Heavily doped base GaInP/GaAs heterojunction bipolar transistor grown by chemical beam epitaxy

The first demonstration of a GaInP/GaAs heterojunction bipolar transistor grown by chemical beam epitaxy is reported. A common-emitter current gain of 30 at a current density of 110 A/cm/sup 2/ is obtained for a beryllium base doping as high as 8*10/sup 19/ cm/sup -3/. The base sheet resistance of 140 Omega / Square Operator is among the lowest reported values.<>     

High linearity power X-band GaInP/GaAs heterojunction bipolartransistor

We report for the first time two-tone test results measured on a GaInP/GaAs HBT. A 2×400 μm² device delivered more than 1.3 W under one-tone testing at 7.5 GHz and output more than 1 W under two-tone. The corresponding intermodulation product is -14 dBc, and decreases to -21 and -36 dBc, respectively, at 3-dB and 10-dB back-off from the saturated two-tone output. These results demonstrate that GaInP/GaAs HBT's are suitable for microwave transmitter applications     

Current transport mechanism in GaInP/GaAs heterojunction bipolartransistors

GaInP/GaAs heterojunction bipolar transistors (HBTs) and both graded and abrupt AlGaAs/GaAs HBTs were fabricated. A total of 20 wafers were analyzed. Comparisons of the experimental results establish that the dominant carrier transport mechanism in GaInP/GaAs HBTs is the carrier diffusion through the base layer. This suggests that the conduction-band barrier across the GaInP/GaAs emitter-base junction is so small that the barrier spike does not affect the carrier transport. This result differs from other published results which, by studying device structures other than HBTs, determined the conduction band barrier to be as large as ~50% of the bandgap difference. The findings of the present investigation, however, agree well with another published work which also examined an HBT structure. The difference between these works is discussed     

Excess noise reduction in GaInP/GaAs heterojunction bipolartransistors

In this paper an annealing procedure which gives an excess noise reduction both of heavily C-doped resistive structures and GaInP/GaAs Heterojunction Bipolar Transistors (HBTs) of 5 dB is proposed. The investigation of the correlation between the noise generators indicate that the annealing leads to a decrease of noise voltage attributed to a strain reduction both in the intrinsic and in the extrinsic base related to a site switching effect of carbon atoms. The reduction of noise current with annealing is attributed to the surface improvement related passivation process by hydrogen atoms     

High-gain GaInP/GaAs heterojunction phototransistor utilising guard-ring structure

GaInP/GaAs heterojunction phototransistors with an emitter guard-ring contact are fabricated. The gain and speed of response of a device is significantly improved by the application of bias to the guard-ring, indicating that the recombination current is surface-dominated and that the quality of the GaInP/GaAs heterojunction interface is high.<>     

Improved emitter transit time using AlGaAs-GaInP composite emitterin GaInP/GaAs heterojunction bipolar transistors

A new emitter structure based on composite graded AlGaAs-GaInP approach is described, which allows significant reduction of CBE and improved high-frequency performance. A theoretical study of the composite and conventional emitter HBTs is performed to prove the superiority of composite emitter HBTs using Monte Carlo simulation of their transport properties. The self-aligned HBTs fabricated in this study are grown by CBE with TBA/TBP precursors. The current gain cutoff frequency (f_T) was 62 GHz for the composite emitter design HBT, and 45 GHz for conventional emitter design HBT. The CBE achieved with the composite emitter designs was at least 3 times lower than that of conventional designs and does not show significant variation with collector current. This leads to enhanced f_T characteristics by 15% for composite emitter HBT designs and confirms the theoretical expectations     

Comparison of GaInP/GaAs heterostructure-emitter bipolartransistors and heterojunction bipolar transistors

Carbon-doped GaInP/GaAs heterojunction bipolar transistors (HBT's) and heterostructure-emitter bipolar transistors (HEBT's) grown by MOCVD were fabricated. Experimental comparison of HBT's and HEBT's has been made based on the dc and the RF performance. HBT's have higher current gains than those of HEBT's in the high current regime, while HEBT's offer a smaller offset voltage and better uniformity in dc characteristics across the wafer. The current gain and cutoff frequency of the DEBT with a 150 Å emitter set-back layer are comparable to those of HBT's. DC (differential) current gains of 600 (900) and 560 (900) were obtained at a collector current density of 2.5×10⁴ A/cm² for the HBT and HEBT, respectively. The cutoff frequencies are 37 and 31 GHz for the HBT and HEBT, respectively. It is shown that there is negligible contribution of the diffusion capacitance to the emitter capacitance in HEBT's with a thin emitter set-back layer but not with a thick emitter set-back layer. The behavior of HEBT's both in dc and RF characteristics is similar to that of HBT's     

A high-frequency GaInP/GaAs heterojunction bipolar transistor withreduced base-collector capacitance using a selective buriedsub-collector

A C-doped GaInP/GaAs HBT using a selective buried sub-collector has been fabricated by two growth steps. The device was fabricated with minimum overlap of the extrinsic base and the sub-collector region to reduce base-collector capacitance. The experiment shows that the base collector capacitance is reduced to about half of that of an HBT without selective buried sub-collector while the base resistance remains unchanged. A current gain of 35, f_T of 50 GHz and f_max of 140 GHz are obtained with this technology     

Extrinsic base surface passivation in GaInP/GaAs heterojunctionbipolar transistors

The authors demonstrate excellent passivation of the extrinsic base surfaces in GaInP/GaAs heterojunction bipolar transistors (HBTs) having small emitter areas. Passivated devices with an area as small as 4×20 μm² exhibit the highest reported current gain value of 2690 for GaInP/GaAs HBTs, while unpassivated 4×20-μm ² devices exhibit a current gain of only 500. Measured current gains as a function of collector current density are almost identical for devices with varying emitter widths of 4, 6, 8, 12, 16, and 100 μm. The current gains are also nearly identical for devices with varying passivation ledge widths of 1, 2, 3, and 6 μm. These results are contrasted with those of a previously published study reporting surface passivation for a GaInP/GaAs HBT with a large emitter area     

On the short and long term degradation of GaInP/GaAs heterojunction bipolar transistors

This work deals with the short and long term effects of a current stress performed at room temperature on Carbon doped GaInP/GaAs heterojunction bipolar transistors. The investigation has been carried out by means of DC characterizations and low frequency noise (LFN) measurements in the 250 Hz–100 kHz frequency range. During the stress the devices were biased in the forward active region; a collector–emitter voltage of 7.7 V and a collector current density of 2.2×10⁴ A/cm² were imposed. The effect of the stress on the DC and LFN characteristics were compared and discussed in terms of two recombination mechanisms. The discussion points out that both extrinsic and intrinsic recombination processes have to be taken into account in order to justify the short and long term effects of the electrical stress.     

Localized deposition of GaAs/GaInP heterostructures using LP-MOVPE

GaInP layers were grown selectively by low pressure MOVPE in patterned SiO₂ masks on GaAs (100) substrates. The variation of the composition and spontaneous ordering phenomena were analysed by Raman spectroscopy and photoluminescence. In contrast to GaInAs, the composition of GalnP shows only a very weak dependence on the size of the structures. On the other hand, there is a shift of the bandgap energy up to 40 meV with decreasing size of the stripes caused by ordering of the Ga and In atoms. Based on these findings lattice matched GaAs/GalnP multilayers were grown to delineate the growth history of the structures. It was demonstrated that the growth habit of deposition in narrow slits (>1μm) can be used to produce mesa-like stripes with dimensions below 100 nm on top of the mesa. Results of GaAs/GaInP quantum wells selectively grown on top of a mesa are presented.     

Growth characteristics of hydride-free chemical beam epitaxy and application to GaInP/GaAs heterojunction bipolar transistors

We report on the complete characterization of a hydride- and hydrogen-free chemical beam epitaxy (CBE) process for the realization of GaAs/GaInP heterojunction bipolar transistors. Alternative group V sources tertiarybutylarsine, tertiarybutylphosphine, and trisdimethylaminoarsenic are used instead of traditionally employed AsH₃ and PH₃. A very high degree of reproducibility of growth parameters (fluxes, substrate temperature, doping levels) is demonstrated. Total defect densities lower than 10 def/cm² are routinely obtained. Large-area GaInP/GaAs heterojunction bipolar transistors (HBTs) show a high current gain of 225 for base sheet resistance of 400 ohm/sq. The devices also exhibit excellent high-frequency characteristics. A cut-off frequency of 48 GHz and a maximum oscillation frequency of 60 GHz have been obtained. These results demonstrate the high potential capability of CBE for high-throughput GaInP/GaAs HBT production.     

自对准GaInP/GaAs HBT器件

利用发射极金属掩蔽进行内切腐蚀的方法研制成自对准InGaP/GaAs异质结双极晶体管 (HBT),其特征频率(ft)达到54GHz,最高振荡频率(fmax)达到71GHz,并且,这种方法工艺简单,成品率高.文中还对该结果进行了分析,提出了进一步提高频率特性的方法.     

自对准GaInP/GaAs HBT器件

利用发射极金属掩蔽进行内切腐蚀的方法研制成自对准InGaP/GaAs异质结双极晶体管 (HBT),其特征频率(ft)达到54GHz,最高振荡频率(fmax)达到71GHz,并且,这种方法工艺简单,成品率高.文中还对该结果进行了分析,提出了进一步提高频率特性的方法.     

GaInP/GaAs double heterojunction bipolar transistor with highfT, fmax, and breakdown voltage

We report on the dc and microwave performance of an MOCVD-grown carbon-doped GaInP/GaAs double heterojunction bipolar transistor (DHBT) with a thin highly doped n-type GaInP layer in the collector. The DHBT showed improved current-voltage characteristics at low collector-emitter bias compared with those of a DHBT without the heavily doped GaInP layer, while maintaining a high breakdown voltage (BV_CEO~20 V). Small area, self-aligned emitter transistors with two 2×5 μm² emitter fingers were fabricated and exhibited f_T and f_max of 53 GHz and 75 GHz, respectively. These results indicate the promise of carbon-doped base GaInP/GaAs DHBT's for high-power microwave applications     

A broad-band amplifier using GaAs/GaAlAs heterojunction bipolartransistors

A compact wideband amplifier (or gain block) designed around a Darlington pair of GaAs/GaAlAs heterojunction bipolar transistors (HBTs) is discussed. This circuit has been fabricated by an ion-implanted process with a transistor f_t of 40 GHz. Two variants of the circuit gave either a 8.5-dB gain with a DC-to-5-GHz 3-dB bandwidth or a 13-dB gain with a DC-to-3-GHz bandwidth. These amplifiers gave 11.8- and 18.3-dBm output, respectively, at 1-dB gain compression     

钝化边沿的制作及其对GalnP/GaAs SHBT 性能的影响

利用光刻胶形成保护侧墙,用湿法腐蚀来形成发射极钝化边沿.这种方法工艺简单,不需要额外的绝缘介质作为掩膜,也不需要双层腐蚀终止层.研发出了带发射极钝化边沿的GalnP/GaAs单异质结双极型晶体管(SHBT),并对不同尺寸有无钝化边沿的器件特性进行对比,结果表明钝化边沿能有效改善小尺寸器件的直流特性,对器件的高频特性无明显影响.     

钝化边沿的制作及其对GaInP／GaAs SHBT性能的影响

利用光刻胶形成保护侧墙，用湿法腐蚀来形成发射极钝化边沿。这种方法工艺简单，不需要额外的绝缘介质作为掩膜，也不需要双层腐蚀终止层。研发出了带发射极钝化边沿的GaInP／GaAs单异质结双极型晶体管（SHBT），并对不同尺寸有无钝化边沿的器件特性进行对比，结果表明钝化边沿能有效改善小尺寸器件的直流特性，对器件的高频特性无明显影响。     

High-performance carbon-doped base GaAs/AlGaAs heterojunction bipolar transistor grown by MOCVD

High-performance HBTs with a carbon-doped base layer (p=4*10/sup 19/ cm/sup -3/) are reported. The use of carbon as a p-type dopant allows the emitter-base p-n junction to be accurately positioned relative to the heterojunction, and the MOCVD growth method ensures consistency and uniformity of the wafer epitaxial structure. Microwave HBTs with current gains h/sub FE/=50 and f/sub T/ and f/sub max/ values of 42 GHz and 117 GHz, respectively, are reported.<>