MOCVD Grown Si-Doped n+ InP Layers for the Subcollector Region in HBTs
Abstract
This paper describes MOCVD Grown Si-Doped n+InP Layers for the Subcollector Region in HBTs. Subcollector layers in emitter-up HBTs are used to make ohmic contact to the collector region grown immediately above it. Ideally, the n+ subcollector layer should have low electrical resistivity, good morphology and an abrupt high/low doping transition between it and the adjacent undoped collector region. Carrier concentrations in excess of 1x10(exp 19)/cu cm are desirable for low resistance contacts to the subcollector layers. Doping above 1x10(exp 19)/cu cm is reported for Sn (1,2),S,Se and Te dopants(3,4), but memory effects (i.e., continuing of the dopant incorporation into subsequently grown undoped layers) limit their usefulness. Si-doping of InP shows no memory problem (3,4), however maximum carrier concentrations seem to be limited to < 1x10(exp 19)/cu cm similar to Si-doped GaAs (5), above which degraded morphology occurs. Prospects for higher Si dopant saturation levels are seen from a few citations of carrier concentrations up to approx. 2x10(exp 19)/cu cm (6,7) and some of these results suggest that lower growth temperature may be the key to achieving higher Si-doping. Electronic devices, Ion beam technology, VLSI/VH
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1994
- Accession Number
- ADA279686
Entities
People
- A. R. Clawson
- C. M. Hanson
Organizations
- Naval Command, Control and Ocean Surveillance Center