Semi Doped

Vikram Sekar and Austin Lyons
  • 5.0 (19)
  • Technology

The business and technology of semiconductors. Alpha for engineers and investors alike.

  1. 6d ago

    PicoJool's Al Yuen: The Case for GaAs VCSELs in Scale-Up Interconnects

    Al Yuen, CEO of PicoJool, talks with Austin about using VCSELs for scale-up optical interconnects in AI data centers. Al explains why gallium arsenide (GaAs) supply is unconstrained while indium phosphide (InP) is limited, and how PicoJool can leverage existing supply chains to ship in the millions per month. They cover the roadmap from 1.6T to 12.8T, the trade-offs among 8×200G, 16×100G, and 32×50G, and the push to train the next generation of photonics engineers. The spec that changed is error rate. AI needs error-free links (10⁻¹⁰–10⁻¹² vs Ethernet's old 10⁻⁶) because GPUs act as one system — one error stalls the whole job.Single-mode optics can't hit the volume. Built for ~100K city-to-city links; datacenters need millions/month — a 10–50× gapGaAs vs InP is the whole supply story. VCSELs run on unconstrained GaAs; single-mode on constrained InP. 1M units: 8–10 weeks vs a sold-out 8–18 months.One platform, three flavors to 1.6T: 8×200G "fast and narrow," 16×100G LPO low-power, 32×50G NRZ "slow and wide" — pick on power, cost, and BER.12.8T needs no new tech — just more of the same: 64 channels (4×16 array in a finger-sized connector) × 200G, scaling channels, bi-di wavelengths, and lane speed.Capacity isn't the time consuming part — qualification is. WIN runs ~1,000 wafers/week at ~240K VCSELs each, so 1M units = ~10 wafers. The wait is tier-1 (>6 mo) and tier-2 (~3 mo) quals. Chapters: 0:00 Meet Al Yuen and PicoJool 2:29 Inventing the active optical cable 5:03 Engineering mindset, copper limits 8:43 Why VCSELs 13:45 Scale-up and bit error rate 20:09 Unconstrained vs constrained supply 21:53 Indium phosphide bottleneck 25:49 VCSEL design and foundry handoff 31:59 Product road map, 200G launch 34:16 Path to 3.2T and 12.8T 40:10 Ordering a million VCSELs 45:10 Ramp timing and training new engineers Follow Chipstrat: Newsletter: https://www.chipstrat.com X: https://x.com/chipstrat Follow Vik: Newsletter: https://www.viksnewsletter.com/ X: https://x.com/vikramskr Follow Semi Doped: Get more of Austin and Vik daily, free! Sign up: https://daily.semidoped.com/

  2. Jul 10

    WEKA's Val Bercovici: KV Cache, DeepSeek V4, HBF, SLC vs QLC NAND, CXL, NVLink, Tokenomics

    Vik welcomes Val Bercovici from Weka to discuss the rapidly evolving landscape of AI memory and storage. Val explains how Weka's architecture leverages high-bandwidth networks to make storage faster than motherboard DRAM. They dive into KV cache optimizations, the future of NAND flash tiers, and the role of CXL in AI inference. The episode concludes with a look at predictive memory offloading and the AI flywheel. Chapters: 0:00 Welcome Val Bercovici, Weka 1:59 Memory situation and model routing 3:50 KV cache offloading to CMX 6:10 Network faster than motherboard 13:10 Weka as AI memory infrastructure 14:45 Inference market is different 16:06 Memory hierarchy and KV cache 19:40 KV cache optimizations and demand 25:20 DeepSeek's cache read pricing 34:49 NAND flash tiers: SLC vs QLC 43:01 High Bandwidth Flash (HBF) 49:59 CXL versus other interconnects Follow Chipstrat: Newsletter: https://www.chipstrat.com X: https://x.com/chipstrat Follow Vik: Newsletter: https://www.viksnewsletter.com/ X: https://x.com/vikramskr Follow Semi Doped: Get more of Austin and Vik daily, free! Sign up: https://daily.semidoped.com/

  3. Jul 3

    Micron's Record Profits, Apple's CXMT Plea: AI is Eating All the Memory

    Austin and Vik break down the current memory crisis, where AI demand is driving unprecedented profits for memory makers like Micron, while simultaneously causing inflation and price hikes for consumer electronics. They discuss how even premium brands like Apple are struggling to secure supply, leading them to controversial suppliers. The hosts also explore the long-term implications of AI's insatiable memory appetite and its impact on both data center and consumer markets. Chapters: 0:00 Memory crisis hits 1:20 AI impacting consumers 3:00 AI causing inflation 6:48 Consumer demand drop? 8:49 AI demand inelastic 10:56 Long-term memory outlook 11:02 GoPro's memory woes 12:24 Apple's pricing power 18:20 Apple seeks CXMT DRAM 21:38 Shrinkflation for phones 23:16 Korea's memory investment 26:10 Micron's killing profits 33:00 Why AI needs so much DRAM 40:27 Future of AI training 44:34 Cost-optimizing inference Follow Chipstrat: Newsletter: https://www.chipstrat.com X: https://x.com/chipstrat Follow Vik: Newsletter: https://www.viksnewsletter.com/ X: https://x.com/vikramskr Follow Semi Doped: Get more of Austin and Vik daily, free! Sign up: https://www.semidoped.com/

  4. Jun 29

    Qualcomm's HBC Memory, Alphawave, Modular, and more

    Qualcomm flew Austin to New York for its investor day, where the communications company laid out a plan to make data center, automotive, and IoT two-thirds of its business by FY29. Austin was in the room and asked Cristiano Amon a question on the record. Vik watched the whole thing on YouTube. Together they break down what actually changed. The technical centerpiece is High Bandwidth Compute (HBC): stacking LPDDR on top of logic to expose the whole face of the chip for interconnects, claiming up to 100x more lanes and a path around the HBM bandwidth bottleneck. Austin and Vik dig into what's really under that memory, why "no advanced packaging needed" just moves the hard problem somewhere worse, and how it compares to d-Matrix. And as Austin put it: don't let anyone tell you HBM is dead. MOAR memory. Then the roadmap: the AI200/250/300 accelerators, the C1000 server CPU (5 GHz, 250+ cores, Meta as a customer), the Alphawave and Modular acquisitions, and Chris Lattner's Mojo. The most interesting takeaway might not be the data center at all. Qualcomm's edge play — AI-defined vehicles, cars as token generators, and a $1T robotics opportunity by 2040 — could be where High Bandwidth Compute matters most.  Chapters:  0:00 Communications? That's just the start  4:08 Inside Qualcomm's investor day  9:16 Can Qualcomm build a data center business?  13:09 Disaggregated inference opens the door  17:57 High Bandwidth Compute: memory on the XPU  30:29 "No advanced packaging" just moves the problem  36:20 The roadmap, Alphawave, and Modular  46:00 The C1000 CPU and the agentic shortage  50:40 Cars as token generators, the $1T robotics bet  57:32 The memory market: MOAR Follow Semi Doped:  Get more of Austin and Vik daily, free!  Sign up: https://www.semidoped.com/ Connect with Vik and Austin:  Vik's Paid Substack: https://www.viksnewsletter.com Austin's Paid Substack: https://www.chipstrat.com

  5. Jun 19

    Advanced Packaging, TSMC CoWoS, Intel EMIB

    New episode: Advanced packaging for AI chips, from wire bonds to TSMC CoWOS and Intel EMIB. Packaging is no longer an afterthought. It is the chip, and Intel's EMIB challenges TSMC's CoWOS. Three CoWOS flavors: silicon, organic RDL, local bridgesEMIB embeds tiny bridges into the substrate, no interposerEMIB-T and EMIB-M add through-silicon vias and power capacitorsGoogle is booking 3M TPUs on EMIB via MediaTek by 2028Package sizes keep climbing: 5.5x reticle today, 40x aheadThis episode is brought to you by SambaNova. Try SambaNova's fast inference today at the SambaNova Dashboard! Connect with Vik and Austin via a daily free newsletter: https://www.semidoped.com Vik's Paid Substack: https://www.viksnewsletter.com Austin's Paid Substack: https://www.chipstrat.com Chapters: (0:00) "There Is No Chip Without the Packaging" (0:28) Intro and SpaceX IPO Day (5:15) What We're Covering: CoWOS, EMIB, Google (7:40) Simple Packaging: Wire Bonds to Flip Chip (17:07) What Makes Packaging "Advanced" (33:44) CoWOS: Three Flavors Explained (45:30) EMIB: Intel's Embedded Bridge Approach (52:47) EMIB-T and EMIB-M (57:31) CoWOS vs. EMIB Trade-offs (1:02:18) Google's 3M TPU EMIB Order

  6. Jun 12

    Computex Mania 2026: Optics and Power

    Austin and Vik discuss their recent experience at Computex, where they met for the first time in person after six months of podcasting together. They share insights about the massive show, the people they connected with, and the exciting developments in AI hardware and interconnect technology. Connect with Vik and Austin via a daily free newsletter: https://www.semidoped.com Vik's Paid Substack: https://www.viksnewsletter.com Austin's Paid Substack: https://www.chipstrat.com Chapters 00:00 Meeting in Person for the First Time 03:05 Experiencing Computex: A Massive Show 05:17 Connecting with the Audience: Real-Life Encounters 06:46 Networking with Industry Leaders 10:42 Keynote Highlights: Marvell's Vision 15:11 The Future of Interconnects: CPO and Beyond 22:54 Exploring Optical Interconnects and Future Technologies 25:56 Micro LED Developments and Future Conferences 27:34 Power Innovations in Data Centers 30:54 Intel's Keynote and New CPU Technologies 36:31 Intel Foundry's Advancements and Industry Implications

    Computex Mania 2026: Optics and Power

  7. May 29

    Huawei's Tau Scaling Law: Is the "EUV Killer" Real?

    Huawei dropped a paper claiming 1.4nm-class performance without EUV, and the internet immediately declared ASML dead and US export controls useless. Austin and Vik recorded one day after Memorial Day to unpack what Huawei actually announced at ISCAS 2026 — and why the "EUV killer" headline gets the story backwards. They walk through the tau scaling law (tau is delay, and the idea is to attack it at the system level instead of the transistor), logic folding via hybrid bonding, the Kirin 2026 that doubles transistor count without shrinking, and who can actually manufacture stacked logic. Then the other tau knobs: a unified memory bus and near-packaged optics. Along the way: BESI vs EV Group, die-to-wafer vs wafer-to-wafer bonding, and why hybrid bonding isn't export-controlled the way EUV is. The takeaway is the opposite of the headline. Tau scaling is rational engineering under constraint, it's bullish for ASML (two DUV wafers per product, not fewer), and the moment EUV-enabled fabs stack their own advanced-node wafers, the gap widens instead of narrowing. Bullish advanced packaging, bullish EDA and multiphysics. Chapters: 0:00 The "EUV killer" paper that broke the internet 2:28 What Huawei actually announced at ISCAS 4:00 Tau scaling: optimize delay, not transistors 8:58 The equation and the 10x AI claim 11:05 Logic folding: stacking logic on logic 17:24 Who builds it, and can hybrid bonding be banned? 24:16 Why this is bullish for ASML 29:49 The other tau knobs: memory and optics 35:18 Takeaways: packaging, EDA, multiphysics Follow Semi Doped: Get more of Austin and Vik daily, free! Sign up: https://www.semidoped.com/ Follow Chipstrat: Newsletter: https://www.chipstrat.com X: https://x.com/chipstrat Follow Vik: Newsletter: https://www.viksnewsletter.com X: https://x.com/vikramskr

    Huawei's Tau Scaling Law: Is the "EUV Killer" Real?

  8. May 22

    Lithography Masterclass

    Spend one hour here and you've caught up on the entire arc of semiconductor lithography. Austin and Vik run a masterclass on the technology that decides who gets to make leading-edge chips, and why so few companies can afford to. The thread is economics. An EUV machine runs about $400 million, a new fab needs roughly 15 of them, and the total bill clears $20-30 billion before a single wafer ships. Austin and Vik trace the whole story: Rock's Law and the cost of a fab, what it actually takes to build one, the evolution from 193nm DUV through multi-patterning to 13.5nm EUV, how ASML generates EUV light by exploding falling tin droplets, and the move to high NA and its mirrors. Along the way, the fun history — i-line, krypton fluoride, immersion lithography, and the engineer who started it all by flipping a microscope upside down. Then the part that matters most: where lithography goes next. Two startups, xLight and Substrate, are attacking the cost problem from first principles. xLight wants to decouple the light source from the scanner with a free-electron laser and sell photons as a service. Substrate wants to skip EUV entirely and revive X-ray lithography. If either works, the economics of who can build a fab change completely. Chapters:  0:00 The 13F panic, and today's topic  2:23 Why the real story is economics, not physics  6:18 Austin in the clean room: graphene and bunny suits  10:06 Rock's Law and the $20 billion fab  18:08 DUV, the Sharpie, and a history of light  24:58 Multi-patterning, explained with a football field  34:45 How EUV makes 13.5nm light from tin droplets  41:14 High NA, anamorphic optics, and the half-field tax  46:45 The startups rethinking lithography: xLight and Substrate Relevant reading:  Chipstrat — The economics of lithography: https://www.chipstrat.com/p/lithography-economics Chipstrat — xLight and photons as a service: https://www.chipstrat.com/p/photons-as-a-service Chipstrat — Substrate and X-ray lithography: https://www.chipstrat.com/p/substrate Vik's Newsletter — the viability of X-ray lithography: https://www.viksnewsletter.com/p/an-in-depth-look-at-the-viability Fred Chen — LELE multipatterning and EUV stochastics (Substack): https://frederickchen.substack.com/p/can-lele-multipatterning-help-against Chip War, Chris Miller Focus, Marc Hijink (the ASML book): https://www.amazon.com/Focus-Inside-struggle-complex-machine-ebook/dp/B0CW1FLCD4 Follow Chipstrat:  Newsletter: https://www.chipstrat.com X: https://x.com/chipstrat Follow Vik:  Newsletter: https://www.viksnewsletter.com/ X: https://x.com/vikramskr Follow Semi Doped:  Get more of Austin and Vik daily, free!  Sign up: https://www.semidoped.com/

    Lithography Masterclass
See All (37)

Ratings & Reviews

5
out of 5
19 Ratings

About

The business and technology of semiconductors. Alpha for engineers and investors alike.

Information

  • Creator
    Vikram Sekar and Austin Lyons
  • Years Active
    2026
  • Episodes
    37
  • Rating
    Clean
  • Copyright
    © 2026 Semi Doped
  • Show Website
    Semi Doped

You Might Also Like