Koninklijke Philips Corporation N.v.

Trumpf Photonic Components Gmbh

Bauer Maschinen Gmbh

Alexander Weigl

Holger Joachim Moench

Stephan Gronenborn

Philipp Henning Gerlach

Roman Koerner

Matthias Knoll

Christian Wimmer

Christian Miehling

Rudolf Pöckl

Esef Besic

Alexander HÖFLINGER

Jürgen Kreitmeier

Clemens Kahlenberg

Roman Körner

A method of forming an electrical metal contact within a semiconductor layer stack of a vertical cavity surface emitting laser includes forming a contact hole into the semiconductor layer stack. The contact hole has a bottom and a side wall extending from the bottom. The method further includes providing a photoresist mask inside the contact hole. The photoresist mask covers the side wall of the contact hole and has an opening extending to the bottom of the contact hole. The method additionally includes wet-chemical isotropic etching the bottom of the contact hole, depositing a metal on the bottom of the contact hole, and removing the photoresist mask so that the metal on the bottom of the contact hole is left as the electrical metal contact.

Method of forming an electrical metal contact and method of producing a vertical cavity surface emitting laser

The invention describes a laser device comprising between two and six mesas () provided on one semiconductor chip (), wherein the mesas () are electrically connected in parallel such that the mesas () are adapted to emit laser light if a defined threshold voltage is provided to the mesas (). Two to six mesas () with reduced active diameter in comparison to a laser device with one mesa improve the yield and performance despite of the fact that two to six mesas need more area on the semiconductor chip thus increasing the total size of the semiconductor chip (). The invention further describes a method of marking semiconductor chips (). A functional layer of the semiconductor chip () is provided and structured in a way that a single semiconductor chip () can be uniquely identified by means of optical detection of the structured functional layer. The structured layer enables identification of small semiconductor chips () with a size below 200 &#x3bc;m&#xd7;200 &#x3bc;m.

Compact laser device

The invention describes a laser device () comprising between two and six mesas () provided on one semiconductor chip (), wherein the mesas () are electrically connected in parallel. The laser device () is adapted such that degradation of at least one mesa () results in a decreased laser power emitted by the laser device () in a defined solid angle when driven at the defined electrical input power. The laser device () is adapted such that eye safety of the laser device () is guaranteed during life time of the laser device (). Eye safety may be guaranteed by designing the semiconductor structure or more general layer structure of mesas () of the laser device () in a way that degradation of one or more layers of the layer structure results in a reduction of the maximum optical power emitted in a defined solid angle. Alternatively or in addition, the electrical input power supplied to the laser device () may be controlled and adapted depending on the emitted optical power such that safety limits are not exceeded. The invention further relates to a laser module and an optical sensor () comprising such a laser device () and mobile communication device () comprising such an optical sensor (). The invention further relates to a method of manufacturing such a laser device ().

Safe laser device for optical sensing applications

The present invention relates to a laser device being formed of at least one VCSEL () with intracavity contacts. The VCSEL comprises a layer structure () with an active region () between a first DBR () and a second DBR (), a first current-injection layer () of a first conductivity type between the first DBR () and the active region (), and a second current-injection layer () of a second conductivity type between the second DBR () and the active region (). The first and second current-injection layers () are in contact with a first and a second metallic contact (), respectively. The first and/or second DBR () are formed of alternating Aluminum oxide and Al(x)Ga(1&#x2212;x)As containing layers. The proposed design of this VCSEL allows an increased efficiency and lower production costs of such a laser since the top and bottom DBRs may be formed of a considerable reduced thickness.

VCSEL with intracavity contacts

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Ulm, Germany

Alexander Weigl