Accurate in-situ lattice matching by reflection high energy electron diffraction
US5631472A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 7, 1995 |
| Grant date | May 20, 1997 |
| Priority date | — |
| Expiry date | Jun 7, 2015 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S438/938
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
An in-situ method is disclosed for highly accurate lattice matching using reflection high energy electron diffraction dynamics. The method includes the steps of providing a substrate of a first semiconductor material and initiating growth of a second semiconductor material thereon. The oscillation amplitude of intensity I of waveform cycles is monitored using reflection high energy electron diffraction. A maximum intensity I.sup.+ and a minimum intensity I.sup.- is determined over a predetermined number of waveform cycles. The intensity drop .DELTA.I from initial reflectivity to minimum reflectivity of the waveform cycles is determined and normalized figure of merit FM is calculated for the predetermined number of waveform cycles using the relationship: ##EQU1## The fluxes of the second semiconductor material are then adjusted to maximize FM and optimize matching. A multiple quantum well light modulator is also provided including a semiconductor substrate of InP, a multiple quantum well region, disposed above the InP substrate, composed of InGaAs and having a thickness of about 4 .mu.m. The modulator is characterized by a lattice mismatch of less than 2.times.10.sup.4.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.