Low DC power, high gain-bandwidth product, coplanar Darlingtonfeedback amplifiers using InAlAs/InGaAs heterojunction bipolartransistors

[[abstract]]Broad band amplifiers with two Darlington feedback topologies, namely resistive biased and mirror biased, have been designed, fabricated and characterized. The HBT layers used for amplifiers were grown by MBE. To reduce the knee voltage and increase the breakdown voltage of the devices, graded base-emitter junction and low-doped, thick collector have been employed. The fabricated amplifiers have achieved 10.95 dB gain with 25.5 GHz bandwidth at DC power consumption of only 34.7 mW. State-of-art Gain-Bandwidth-Products per dc power were achieved for both amplifiers (⩾2.60 GHz/mW). The fabricated amplifiers also demonstrated moderate output power (8.3 dBm) at 10 GHz with a low DC power consumption of only 40 mW[[fileno]]2030121030001[[department]]電機工程學

Hole impact ionization coefficient in (100)-oriented In0.53Ga0.47As based on PNP InAlAs/InGaAs HBT's

The hole multiplication factor in pnp In0.52Al0.48As/In0.53G0.47As single heterojunction bipolar transistors (HBT's) has been measured as a function of the base-collector bias. Hole impact ionization coefficient βp has been estimated by taking into account the Early effect, the collector-base leakage current ICBO, thermal effects and the spread in the nominal device processing parameters. Numerical corrections for dead space and current-induced collector charge density variations were made. The data obtained in this way agree with the most recent photomultiplication measurements available in literature

Measurements of the InGaAs hole impact ionization coefficient in InAlAs/InGaAs pnp HBTs

The hole multiplication factor in pnp InAlAs/InGaAs single heterojunction bipolar transistors (HBTs) has been measured as a function of the base-collector bias. The hole impact ionization coefficient beta (p) has been estimated taking into account the Early effect, I-CBO, and thermal effects. Numerical corrections for dead space were made. The importance of considering second order effects is highlighted, showing that rough approximations can lead to an overestimation of the coefficient beta (p). At low electric fields, the extracted coefficient agrees with the most recent photomultiplication measurements available in the literature, At high electric fields, hole impact ionization coefficient is estimated up to values previously not reported in the literature (beta (p) approximate to 10(4) cm(-1))

Measurements of the InGaAs Hole Impact Ionization Coefficient in InAlAs/InGaAs pnp HBTs

Abstract\u2014The hole multiplication factor in pnp InAlAs/In- GaAs single heterojunction bipolar transistors (HBTs) has been measured as a function of the base-collector bias. The hole impact ionization coefficient p has been estimated taking into account the Early effect, ICBO, and thermal effects. Numerical corrections for dead space were made. The importance of considering second order effects is highlighted, showing that rough approximations can lead to an overestimation of the coefficient p. At low electric fields, the extracted coefficient agrees with the most recent photomultiplication measurements available in the literature. At high electric fields, hole impact ionization coefficient is estimated up to values previously not reported in the literature