Accurate in-situ lattice matching by reflection high energy electron diffraction
US5480813A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 21, 1994 |
| Grant date | Jan 2, 1996 |
| Priority date | — |
| Expiry date | Jun 21, 2014 |
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 a 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 lattice 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.