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Investigation of Heterojunction Bipolar Transistors Using Metallic P-Type Base Layer

使用金属 P 型基层的异质结双极晶体管的研究

基本信息

批准号：
01460136
负责人：
KONAGAI Makoto
金额：
$ 3.97万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1990
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-01460136/
关键词：
GaAs MOMBE Trimethylgallium Heavy doping Heterojunction bipolar transistor

项目摘要

To realize ultra-high speed heterojunction bipolar transistors (HBTs), a "metallic" base layer with extremely low base resistance is necessary. In this work, carbon doped metallic p-type GaAs layers were grown by metalorganic molecular beam epitaxy (MOMBE) using trimethylgallium (TMG) and solid arsenic. A hole concentration of 1.5x10^<21> cm^<-3> with a resistivity of 1.9x10^<-4> OMEGAcm has been obtained, which is the highest hole concentration for GaAs reported so far. Furthermore, carbon was found to be much less diffusive than other pーtype dopants, such as beryllium and zin c, even at extremely high doping levels. Therefore, carbon is a promising dopant for the HBT applications. However, at high doping levels, the lattice constant decreases with increasing carrier concentration, which creates a lattice mismatch between heavily carbon doped pーGaAs and moderately doped GaAs. To compensate this lattice mismatch, a small amount of indium was added to grow InGaAs. A hole concentration of 2.6x10^<20> cm^<-3> was obtained for InGaAs (In-5%) lattice matched to GaAs substrate. It was also found that the band-gap of carbon doped GaAs decreases with carrier concentration. Since this shrinkage is as large as 200 meV for a hole concentration of 5x10^<20> cm^<-3>, a pseudo-HBT has been proposed, which uses GaAs instead of AlGaAS for the emitter layer. In pseudo-HBTs, because of the band-gap shrinkage of heavily carbon doped GaAs in the base, a high emitter injection efficiency, and excellent high frequency performance can be expected, as in conventional HBTs. A pseudo-HBT with 100 nm thick base (p=1x10^<20> cm^<-3>) was fabricated and a DC current gain of 1.7 was obtained.

为了实现超高速异质结双极晶体管（HBT），具有极低基极电阻的“金属”基极层是必要的。在这项工作中，碳掺杂的金属p型GaAs层的金属有机分子束外延（MOMBE）使用三甲基镓（TMG）和固体砷生长。获得了空穴浓度为1.5 × 10 ~（-1）cm <21>~ 2<-3>、电阻率为1.9 × 10 <-4>~（-1）Ω·cm ~（-1）的GaAs薄膜，这是迄今为止所报道的最高空穴浓度。此外，发现碳比其它p型掺杂剂（例如铍和锌C）扩散性小得多，即使在极高的掺杂水平下也是如此。因此，碳是一种很有前途的HBT应用掺杂剂。然而，在高掺杂水平下，晶格常数随着载流子浓度的增加而减小，这在重碳掺杂的p型GaAs和中等掺杂的GaAs之间产生晶格失配。为了补偿这种晶格失配，添加少量铟以生长InGaAs。对于<20><-3>与GaAs衬底晶格匹配的InGaAs（In-5%），获得了2.6 × 10 ~（-5）cm ~ 3的空穴浓度。实验还发现，掺碳GaAs的禁带宽度随载流子浓度的增加而减小。由于对于5 × 10 - 4cm-3的空穴浓度，这种收缩高达200 meV<20><-3>，因此已经提出了伪HBT，其使用GaAs而不是AlGaAs作为发射极层。在准HBT中，由于在基极中重掺碳的GaAs的带隙收缩，可以预期高发射极注入效率和优异的高频性能，如在常规HBT中一样。制作了基区厚度为100 nm（p= 1 × 10 ~（-6）<20>cm ~（-1<-3>））的准HBT，获得了1.7的直流电流增益。