新型恒压控制型负阻HBT的研制进展

Study of Novel Voltage-Controlled Negative Differential Resistance HBT

研究了HBT产生负阻的可能机制,通过对材料结构和器件结构的特殊设计,采用常规台面HBT工艺,先后研制出3类高电流峰谷比的恒压控制型负阻HBT。超薄基区HBT的负阻特性是由超薄基区串联电阻压降调制效应造成的,在GaAs基InGaP/GaAs和AlGaAs/GaAs体系DHBT中均得到了验证。双基区和电阻栅型负阻HBT均为复合型负阻器件。双基区负阻HBT通过刻断基区,电阻栅负阻HBT通过在集电区制作基极金属形成集电区反型层,构成纵向npn与横向pnp的复合结构,由反馈结构(pnp)的集电极电流来控制主结构(npn)的基极电流从而产生负阻特性。3类负阻HBT与常规HBT在结构和工艺上兼容,兼具HBT的高速高频特性和负阻器件的双稳、自锁、节省器件的优点。

Negative differential resistance （NDR） mechanisms of HBT were studied. Three kinds of high current peak-to-valley ratio NDR HBTs were fabricated successively adopting general mesa HBT technology and particularity design of material and device structure. The NDR of ultra thin base HBT comes from the vohagedrop modulation effect of base series resistance and was validated in InGaP/GaAs and A1GaAs/ GaAs system DHBT on GaAs substrate. Dual base NDR HBT and resistive gate NDR HBT are composite NDR devices. In order to form composite structure of longitudinal npn and lateral pnp, the former etches off base region and the later deposits base electrode on collector region. The NDR comes from the control of lateral pnp collector current to longitudinal npn base current. Three kinds of NDR HBT are all compatible with general mesa HBT on structure and technology, and have the high speed and high frequency characteristic of HBT and the bistability, self-latch and save device characteristic of NDR device.