A 210-GHz f/sub T/ SiGe HBT with a non-self-aligned structure

Abstract

A record 210-GHz SiGe heterojunction bipolar transistor at a collector current density of 6-9 mA/ m 2 is fabricated with a new nonself-aligned (NSA) structure based on 0.18 m technology. This NSA structure has a low-complexity emitter and extrinsic base process which reduces overall thermal cycle and minimizes transient enhanced diffusion. A low-power performance has been achieved which requires only 1 mA collector current to reach 200-GHz . The performance is a result of narrow base width and reduced parasitics in the device. Detailed comparison is made to a 120-GHz self-aligned production device.

Low-resistance n-type polycrystalline InAs grown by molecular beam epitaxy

“…Polysilicon contacts to the extrinsic base placed over dielectric spacer layers have been successfully employed to reduce base-collector capacitance [1], while polysilicon emitter contacts are used as both the contact and diffusion source in self-aligned bipolar transistors [2,3]. There has been a recent trend in SiGe HBTs towards 100 nm emitter widths [4][5][6]. As emitter widths move towards 100 nm, some attention has been given to the optimization of the extrinsic polycrystalline electrode to reduce resistance in the narrow emitter contact [7].…”

Evaluating and designing the optimal 2D collector profile for a 300GHz SiGe HBT

“…More important, however, is the design of the SIC doping profile, which has a strong impact on the carrier transit time through the transistors base, collector, and intermediate depletion zone [3]. Therefore the collector profile is usually a trade-off between speed (f t ), C cb , break down voltage (BV ceo ), and unity power gain (f max ).…”

Growth of SiGe film by using a single-wafer rapid thermal processing UHV/CVD system

“…Si/SiGe strained heterojunction structure is an synthetic material developed using bandgap engineering technology. The SiGe heterojunction bipolar transistor (HBT) boasts excellent performance including high cut-off frequency and maximum oscillation frequency, low noise, large current gain, and better low-temperature characteristics [1][2][3]. Due to their lower power consumption and lower manufacturing costs, integrated circuits employing SiGe HBTs are likely to offer strong competition to III-V products in the wireless communications market.…”