Stripe Mesas Research Articles

Influence of MOVPE growth conditions and CCl 4 addition on InP crystal shapes

Growth of InP with metalorganic vapour phase epitaxy (MOVPE) around reactive ion etched stripe mesas has been studied. The mesas were oriented along the [110] and [1 1 0] directions. Marker layers of different doping were introduced in order to follow growth with respect to time. The growth parameters were varied in order to investigate the influence of reactor pressure, V/III ratio, substrate temperature and addition of CCl 4 on the overall growth behaviour. The final crystal shape could, in general, be well described in Wulff diagrams. The results are discussed with respect to diffusion, chemical reactions and surface kinetic aspects. The significant improvement of regrowth properties observed when CCl 4 was added is most probably due to Cl adsorption to group V sites, acting as an inhibitor for P adsorption and hence restricting growth on {111} planes. With CCl 4 present, the reactor pressure and V/III ratio could be used to further control growth on the {111}A and {110} planes. Due to the asymmetry between {110} and {1 1 0} planes, the growth habit was found to be sensitive to the slope of the mesa walls. However, the effect of this sensitivity was diminished when adding Cl.

Improved InP regrowth properties in metalorganic vapor phase epitaxy by addition of CCl4

Selective and planar regrowth of InP around stripe mesas up to 5.5 μm height formed with reactive ion etching in InP substrates has been made with metalorganic vapor phase epitaxy by adding CCl4 to the process gases. CCl4 seems to prevent nucleation on the phosphorous-rich {111}B lattice planes and on the silicon-nitride cap at the top of the mesa and hence permits reproducible regrowth with desired morphologies for integration of optoelectronic circuits at mesas oriented along the [110] direction. The addition of CCl4 does not influence dopant capability or the semi-insulating properties of Fe-doped material, for which a resistivity of 1×109 Ω cm has been obtained.

Practical solutions to transistorized FM tuner design problems using new epitaxial stripe mesa transistors

The purpose of this report is to analyze some of the design and performance problems associated with f-m tuners and show how these problems may be minimized or eliminated by using the new Texas Instruments TI-390 series germanium epitaxial mesa transistor. The problems to be presented and discussed will include noise performance, spurious responses, and AGC. The relationship of transistor parameter specifications to these problems will be analyzed.